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Digital PBXs: The Architecture of Choice for Voice-Data Integration.

Increasingly, digital PBXs are becoming the architecture of choice for organizations seeking to integrate their voice and data communications operations. Building on the sophisticated voice capabilities of the modern PBX, new firms such as Ztel and CXC have come to the aid of data users with "fourth-generation" systems that marry the complementary functions of local-area network and digital switch. Northern Telecom has also integrated a local-area network with a digital PBX to provide a 40-Mb/s dynamically allocated system bandwidth and a 2.56-Mb/s "pipeline" to each desk. Meanwhile, Harrris' Digital Telephone Systems Division has introduced its own version of a fourth-generation PBX based on a powerful tandem-switch architecture that can reportedly reduce long-distance communications costs by as much as 30 percent.

Not to be outdone, industry pioneers such as Rolm Corporation and third-generation proponents such as InteCom have moved to accommodate local-area networks and integrate them into their PBX architectures. AT&T Information Systems has also been busy upgrading its digital PBX offerings, along with other industry stalwarts, GTE and ITT. Further, a number of major foreign firms, including NEC Telephones, Siemens and Ericsson, have been successfully selling their systems to US firms implementing office-automation systems. What's more, data users can now choose from a wide variety of data-only PBXs, which owe their heritage to switching versions of intelligent multiplexers.

Ztel Bounces Back from Reorganization

Ztel has emerged from its Chapter 11 reorganization of the summer with a court-approved recapitalization plan, a new management team and strengthened relationships with distributors. "We've hit a lot of milestones over the last few months and teh resulting enthusiasm and commitment have had a measurable impact on the company as a whole," reports Murray H. Bolt, president and chief executive officer of the Wilmington, Massachusetts, firm. "Ztel has signed or formalized agreements with seven distributors. We've recruited and installed a new top-management team. Our product-development schedule is on target. And we got a terrific response and generated new, positive interest from our appearance at the TCA show in September."

Ztel's Private Network Exchange (PNX) integrates digital-PBX technology with local-area network capabilities to link telephones, personal computers, word processors, workstations, facsimile machines and mainframe computers into a single communications system. "Ztel is committed to the capabilities of the PNX to serve as a point of resource concentration for voice and data communications," Bolt says. "As such, the market can expect us to support all of the current and evolving LAN configurations so the PNX can function as a gateway in a single or multi-LAN environment."

Up to 1,500 voice and data terminals can be attached to each basic PNX node, or System Processing Unit (SPU), and a single PNX can incorporate up to 256 SPUs. The system can grow from 200 to over 50,000 ports. Multiple SPUs can be interconnected via two types of rings: circuit rings, which carry all voice traffic and data at speeds to 56 kb/s, and an integrated token-ring local-area network that is compatible with the IEEE 802.5 draft standard for token-passing ring networks. Ztel claims the network will also be compatible with IBM's recently announced token-passing ring LAN. Voice traffic travels at 64 kb/s on the circuit rings, which can each support 113 simultaneous conversations.

Coax circuit rings can extend up to five miles; for greater distances, users can turn to fiber-optic cable or to microwave, satellite or T1 carrier facilities.

SPUs contain subsystems that perform applications processing such as least-cost routing, switch processing and data conversion. Most SPUs contain all three subsystems, but in some cases an entire SPU may be dedicated to performing applications such as data or word processing. One package allows users to implement a powerful office-wide messaging system. Also included in the package is an integrated on-line directory for the PNX's CRT-based attendant console, as well as options for helping a system manager track internal calls and collect various types of statistics. Another option allows users to originate calls directly from a keyboard attached to a personal computer or terminal.

In June, Ztel announced tenant-support capability for the PNX, enabling a propety's communications manager to provide shared voice and data communications service on a single PNX system to multiple tenants in a property. Another software package, Enhanced Networking and System Control, reportedly allows a firm to easily integrate the system into existing private networks and, in many cases, to utilize the PNX's advanced capabilities to improve network performance and increase network control. The software also provides PNX users with a controlled environment for expanding single-site systems to multi-site capabilities.

According to Bolt, the PNX's ability to cost-effectively expand with users' demands has proved to be a big selling point with both distributors and end users. "We are aggressively gearing up to meet two new, distinct line-size markets that will further enhance the system's modularity," he says, adding that the systems are scheduled to be announced at this month's NATA convention in Dallas.

To go with its PBX, Ztel offers three all-digital telephones. Two of the sets have separate user-initiated feature buttons, retaining familiar keyset capabilities and providng calling features accessed by a single button. One telephone set contains a 40-character display and 28 feature keys that can be assigned to popular messages such as "call me back" or "returned your call," allowing a caller to send selected messages to the designated telephone if the line is busy or if there is no answer.

CXC Unifies Voice/Text Messaging

CXC's Rose system also integrates a digital PBX with a local-area network to provide a fully distributed switching and communications processing system with dynamic allocation of bandwidth and a packet data channel to each terminal. CXC claims that Rose is the first system to integrate voice mail, text mail and message store-and-forward capabilities architecturally and to employ variable-bandwidth-per-line switching, a proprietary technology made possible through the use of custom VLSI circuits. A low-speed data call of up to 4.8 kb/s, for example, is allocated 8 kb/s, whereas a voice call uses 64 kb/s and a high-speed data connection may use up to 512 kb/s. An inactive or unassigned station uses no bandwidth.

According to the Irvine, California, firm, the key to the system's functionality is its use of sophisticated and extensive voice and data call-message processing software. System applications range from a full complement of traditional PBX voice functions and communications cost-management packages to full-featured voice and text messaging and mail. Both circuit and packet switching support a communications network that's capable of integrating word processing, graphics, personal-computer applications and, in future releases, video teleconferencing systems.

A single node supports up to 192 full-duplex, nonblocking ports for telephones, CXC teleterminals and data terminals. Presently, 64 nodes can be interconnected to support more than 12,000 ports, and individual nodes can be configured as gateways to interface with other networks. CXC says that future releases will support more than 25,000 ports by interconnecting up to eight rings in one system.

The nodes are interconnected via a proprietary local-area network that combines both baseband and broadband technologies. A broadband ring operates at 50 Mb/s and supports circuit switching of voice and data at a combined throughput of 3 Mb/s using a proprietary RF modem and standard CATV technology. The additional capacity is reserved for four 4-Mb/s token-ring bands compatible with the IEEE 802 standard and IBM's LAN offering. Meanwhile, the Ethernet baseband LAN is being used on an interim basis for control interfaces between nodes and for packet-switched data. When the IBM-compatible or IEEE 802 token-passing rings are integrated into the broad-band channel to provide a single coaxial broadband transmission system for voice, data and packet data, the present Ethernet interface will become an optional gateway.

CXC has also designed a "personal teleterminal" to complement the Rose system. It includes an 80-character display and a keyboard for typing in text messages that can be entered concurrent with normal phone usage. Text messages are recorded on disks. The recipient is notified of pending messages on the 40-character display. Messages can be scrolled, scanned, read, replied to immediately or acknowledged. Distribution lists, predefined speed messages and regiestered-mail messages are available features.

Data terminals plug directly into the RS-232 port on the teleterminal and require no external modems. They support asynchronous data rates to 19.2 kb/s and synchronous communications to 128 kb/s, full duplex. Packet communications are supported at rates to 9.6 kb/s. Harris Strengthens Network Role

Harris' 20-20 PBX uses a powerful tandem-switch architecture to provide optimal performance not only in the office but in corporate networks as well. "The Harris approach differs from that of most manufacturers, who have simply added tandem software in Band-Aid fashion to an existing PBX," says Don Green, vice president and general manager of Harris' Digital Telephone Systems Division. "Though the systems are effective in handling routine office switching, they tend to be unreliable or insufficiently powerful in a network environment."

According to Green, the 20-20 PBX can reduce long-distance communications costs by as much as 30 percent for single-site installations and for organizations with private networks. Also, because the system's tandem routing protocols are compatible with switches from most major suppliers, private networks incorporating the Harris 20-20 PBX can include equipment from a mix of vendors. Thus, communications managers can economically build or upgrade networks by using Harris 20-20 PBXs to replace only those network nodes that are fully depreciated, Green points out.

The system's cost savings result from its ability to provide desk-to-desk communications without the exclusive need for increasingly costly private leased lines. The system provides an economical alternative to leased facilities by establishing extended software-defined networks; that is, "virtual" networks consisting of private-leased analog or T1 lines, WATS, DDD and other common-carrier facilities. If a direct path on the dedicated network is not available, the system will automatically direct the call over the most economical alternate route, using any combination of public and private facilities. This means that private networks utilizing one or more Harris 20-20s require fewer leased lines, since other facilities can be called into service during peak traffic hours.

In an office environment, the Harris 20-20 provides the capability for workstation-to-workstation communications and for workstation-to-computer communications, using either standard twisted-pair wiring or high-speed digital multiplexed interface links. It can also serve as a gateway to wide-area networks for office workstations. Green reports that the 20-20 will also be an integral part of Harris' office-automation product offering, which currently includes workstations, networked office systems and a wide array of office-automation software. Future releases of the 20-20 and of Harris office networks will allow attached workstations to access voice mail, electronic mail, data bases, electronic filing and document archiving functions in an integrated PBX/LAN environment.

The Harris 20-20 PBX features nonblocking operation for 1,920 ports and employs pulse-code modulation and time-division multiplexing for transmission in both North American T1/D3 and international CCITT digital formats. By switching multiple time slots of 64 kb/s with clear-channel signaling, the PBX supports data-transfer speeds to 2.048 Mb/s. Using Harris' data-communications adapter (DCA), the system supports IBM 3270 and X.25 protocols. It also communicates with RS-232, RS-449/422 and V.35 interfaces, enabling data to be switched with local-area networks. Asynchronous data can be switched at speeds to 19.2 kb/s, with synchronous transmission to 64 kb/s.

Harris has also designed an intelligent station set, the Optic Teleset, to take advantage of the 20-20 capabilities. A fully digital telephone with alphanumeric display, the Optic Teleset offers such features as messaging, call screening and speed dialing. It also supports Harris' PinkSlip Messaging Feature, which enables the telephone attendant to store messages on the PBX and distribute them electronically. When the Teleset indicates that messages are waiting, they can be viewed at the user's request on an integrated 40-character display.

Prices for the Optic Teleset range from $350 to $700 installed, depending on the feature selected. Prices for the 20-20 PBX range from $400 to $800 per line, depending on size and system configuration.

InteCom Upscales Its Third-Generation IBX

InteCom, which launched the third-generation PBX with its Integrated Business Exchange (IBX), has also integrated a local-area network within its design. Its LANmark uses standard twisted-pair telephone wire to allow office devices to communicate with each other at burst-mode speeds to 10 Mb/s. In addition, LANmark integrates voice and network packet-switching into the star architecture of the IBX, providing up to 512-Mb/s bandwidth in full-duplex mode.

The IBX architecture features three layers, starting at the hub with the Master Control Unit (MCU), which comprises two powerful 32-bit processors: an on-line processor backed up by a secondary one that assumes all activity should a malfunction occur. The next layer features up to 32 redundant switching networks (SNs) of 256 voice/data paths each. Each pair of SNs contains microprocessors that route circuit-switched data, voice and packet transmissions to their different destinations. The outermost layer contains up to 32 interface multiplexers (IMs) that radiate from the SNs. Each IM houses up to 256 voice/data ports and can be centrally located with the MCU or extended to 25,000 feet from the MCU with redundant fiber-optic cable.

The IBX voice/data ports support the firm's digital telephones, called Integrated Terminal Equipment (ITE). The ITE offers standard business-machine interfaces and can handle synchronous and asynchronous communications at any rate from 110 b/s to 56 kb/s. Telephone conversations are digitized within the ITE, merged with data signals and transmitted over the IBX's network of two-pair telephone wire.

The Allen, Texas, firm also supplies a family of packet-based controllers, called InteNet, that perform the format and protocol conversions needed to allow a range of dissimilar business machines to communicate with each other via the IBX. One controller, the Inte-Net Packet Controller (IPC) allows IBM and Wang word processors to communicate with each other. Another, the X.25 IPC, gives up to 16 user ports simultaneous use of a single X.25 network link for sending data and voice. The latest unit, the 3270 IPC, supports IBM Bisync and SNA protocols as well as a variety of asynchronous terminals and personal computers, offering dial-back data security.

In May, InteCom expanded its product offering with the IBX S/80+, which is designed for organizations needing more than 20,000 lines. The unit's master control unit offers the enhanced processing speed and memory needed by the larger-sized system user. In addition, the S/80+ accommodates up to 62 interface multiplexers, for a total of 16,384 voice/data ports. Options developed for use with the IBX S/40 and S/80, such as the IPCs, also function with the S/80+.

Announcement of the IBX S/80+ came in the wake of InteCom's introduction of its B Series of telephones. Designed to increase reliability and facilitate maintenance, the ITE B12 button and ITE B24 display-button styles join three other telephone models supported by IBX systems. The ITE 12 features 12 function buttons, each with an associated lamp to indicate the status of the call or feature. The ITE B24 is characterized by a 40-character liquid-crystal display with 24 functions buttons and associated lamps.

At the ICA show in Dallas, InteCom unveiled what it calls an information networking terminal. The result of a joint effort with Wang Labs, which acquired 30 percent of InteCom in 1984, the Keystone terminal reportedly "bridges the voice and data communications features of the IBX with the office automation applications available in Wang products and with other shared resources such as IBM, Digital and Hewlett-Packard." Keystone provides a desktop link to a user's corporate information system via existing IBX twisted-pair networks. Among the product's features are a nine-inch video screen, an integrated electronic digital telephone with 80-character liquid-crystal display, a handset and built-in speakerphone and a Wang universal keyboard. Keystone is being offered to IBX users at a special introductory price of $2,400 through the end of this month.

Rolm Adds Fiber-Optic Links to Its CBX

Rolm's new-generation computer branch exchange, the CBX II, features a distributed architecture that uses fiber-optic links and modular expandability to support from 16 to more than 10,000 users. Its communications-handling capacity is 4,400 Mb/s. The CBX II supports up to 15 nodes, each of which is independent of the others to provide high system-level reliability. Each communications channel within a node can carry data at rates to 192 kb/s. A dynamically allocatable bandwidth feature allows faster devices to use as many channels as needed to carry the required data. With the CBX II architecture, it's possible to have data connections between two devices at rates to 37 Mb/s. High-speed nonblocking internode connections are provided by fiber-optic links that accommodate rates to 295 mb/s between any two nodes in the system. Also, the RolmLink provides a 256-kb/s bidirectional pipeline from digital desktop devices on a single twisted-pair of telephone wiring.

To complement its three digital telephones and Cypress communications terminal, the Santa Clara, California, firm offers two desktop units that combine personal computers with the CBX II system. Cedar combines an IBM PC-compatible computer, a multiline digital telephone with speakerphone, and a variety of personal productivity and communications services in a compact unit that permits fast, easy access to computers and data bases and convenient one-touch dialing of telephone numbers. Juniper is a multiline digital telephone with built-in speakerphone, which connects by cable to an adapter board that plugs into an IBM PC. All members of the digital desktop family connect to the CBX II via Rolm Link.

CBX II users have access to high-speed digital transmission facilities through the Rolm T1/D3 interface, which takes data and digitized voice information and converts it into a T1 data stream at the standard rate of 1.544 Mb/s. In addition, with the Rolm X.25 interface, the CBX II can be used to connect high-speed private data networks for multisite applications. The unit also provides a cost-effective interface to public data networks and public data bases.

In April, the firm announced new capabilities to improve call routing and restriction functions and to provide connection to equal-acess vendors of long-distance telephone services. One product, RolmNet II, includes a capability known as Virtual Private Lines (VPL). VPL duplicates the direct desk-to-desk dialing function of leased lines, using public dial-up phone lines instead. Later in the summer, Rolm introduced an attendant station, the CAS II, which transmits call information to attendants and provides timely, comprehensive information about system performance. It also expanded the capacity for its PhoneMail voice-messaging system on the CBX II 9000. The expanded PhoneMail system can accommodate as many as 8,000 users with up to 128 channels, providing voice messaging and telephone answering at a cost of less than $1 per user per day.

AT&T Has Established an Interface Standard

AT&T Information Systems employs a distributed multiprocessor architecture for its System 75 digital PBX to provide fully integrated voice and data transmission in nonblocking configurations up to 800 lines. Standard features include the capability to transmit voice and 64-kb/s synchronous data simultaneously over the same twisted pairs of lines. Built-in voice capabilities include six-way conferencing for staff discussions and advanced call-management features. To improve office efficiency, the System 75's "busy hour" call-handling capability has been expanded from 1800 to 3600 calls per hour. Data-handling capacity was also expanded, from 200 to 800 data-module end points.

The System 75 has an internal message facility. When a staff member is absent, leave-word calling lets colleagues leave their names and numbers, which the called party can check on a digital voice terminal. An internal directory displays names and numbers on a digital display module. The system also comes with an enhanced menu-driven system management capability that permits customization of features, production of usage reports and diagnostics, all readily accessible to the user. There's also provision for remote diagnostics and maintenance. An average configuration with 400 lines costs about $800 per line.

The System 75 may be linked with other System 75s as well as System 85s in local or nationwide communications networks. The System 85's digital communications processing architecture can be configured to accommodate as many as 32,000 lines and to handle in excess of 45,000 calls per hour. A recent software enhancement to the System 85, called Audix (audio information exchange) allows people anywhere in the world to create, save and receive voice messages electronically. Audix is one part of AT&T's Unified Messaging Plan, which gives businesses the means to combine diverse voice and text message services into a streamlined universal system. Unified Messaging feeds message notifications into an end user's "universal mailbox," provides a visual signal that indicates a message is waiting and identifies the service from which it comes. It also provides a standard interface between in-house messaging services and public services, extending message creation and retrieval capabilities across the country.

AT&T Information Systems recently introduced a "second-generation" digital voice terminal for use with System 75 and 85 digital PBXs. Designed for managers who need advanced voice features and immediate access to messages and incoming call information, the 7407 features an integrated 80-character liquid-crystal display, multiline functionality via one digital line, one-button access to PBX features and telephone numbers, and a built-in speakerphone. The 7407 supports simultaneous voice and data transmission over the same pair of wires when equipped with an optional data interface. The list price for the digital voice terminal is $900.

AT&T Information Systems has been active in opening its digital switched systems to office-automation vendors, including Data General, Datapoint, Hewlett-Packard, Honeywell and Wang Laboratories. All the firms support AT&T's Digital Multiplexed Interface (DMI) for linking the AT&T switches with their host computers for exchanging information. The DMI is a 1.544-Mb/s interface capable of providing up to 23 64-kb/s multiplexed data channels, with the 24th being used for common-channel signaling. NCR Comten is also developing an interface to connect its data communications systems to the DMI for use with the System 75 and 85 digital PBXs.

Northern Telecom Has Developed Enhancements

Northern Telecom has also developed a computer-to-PBX interface (CPI), along with Digital Equipment Corporation, in an effort to make office automation systems more cost-effective. The CPI permits economical data-switching from local or remote terminals to a host computer through a digital PBX over standard two-pair telephone wiring. Compatibility with North American T1 carrier specifications allows the user to employ twisted-pair, fiber-optics or microwave transmission media for local or remote access. Over 50 firms have obtained the CPI license.

In addition, Northern Telecom has been working with Data General, Hewlett-Packard, Sperry and Wang Labs to integrate their computers with its SL-1 digital PBX. Wang Labs has also reached similar agreements with Mitel Corporation and Siemens Communications Systems to perform compatibility testing of Wang equipment with the firms' SX-2000 and Saturn II and III digital PBXs.

In February, Northern Telecom announced a major enhancement of its SL family of PBXs, vastly increasing their capabilities and providing a range of new information system for smaller organizations or individual departments that fully integrates voice, data and text communications, and a range of new digital terminals. The terminals include a sophisticated voice and data terminal, new digital telephone sets, and a radically new telephone set that uses a touch-sensitive screen instead of buttons. The new products and services are part of Northern Telecom's Open World program, which envisions the integration of many information-handling functions and different types and makes of equipment.

The enhanced versions of the SL family are called the Meridian SL-1 and Meridian SL-100 integrated services networks and serve from 30 to 30,000 users. "It is important to recognize that the Meridian SL products do not replace current SL-1 and SL-100 systems," notes Desmond Hudson, president of Northern Telecom. "They build upon them," he explains. "SL systems already installed can be upgraded to become Meridian SLs."

The Meridian SLs incorporate three major architectural extensions: a 40-Mb/s parallel transport system that features dynamic bandwidth allocation, a new multiprocessing architecture associated with the transport, and a 2.56-Mb/s twisted-pair digital distribution system. The Meridian SL-1 and SL-100 incorporate a local-area network, called Lanstar, that allows computers, terminals, telephones and other peripheral equipment to operate on a single network over standard twisted-pair telephone wiring. Lanstar provides a total bandwidth of 40 Mb/s that can be allocated on demand to give users the capacity they need at any given time. Information travels to each desk over standard twisted-pair telephone wiring at 2.56 Mb/s.

The Meridian SL systems also offer a wide range of enhanced communications services, including:

* The ability to create, send and receive text and voice messages, and to add a recorded voice message to a document or a text message for sending to others;

* An electronic directory that could include an entire corporate telephone directory and as many as 1,000 personal entries for each user;

* A service that allows users to design, store, fill in, "sign" and route forms electronically rather than on paper; and

* A computing capability that supports applications software from independent vendors, including word processing, calendar management and data-base management.

"The Meridian SL systems serve the centralized communications needs of organizations ranging in size from small to very large," says Hudson. "For departmental operations with significant computing requirements or for smaller self-contained offices, such as branch offices, professional practices or small businesses, we have introduced the Meridian DV-1 data/voice system."

A modular system built around shared processors, the Meridian DV-1 offers a similar 40 Mb/s local-area network capacity and the same 2.56-Mb/s distribution system as the Meridian SL systems. The Meridian DV-1s flexible architecture allows it to support multiple industry-standard operating systems and a variety of powerful multiprocessors within the same system. As a result, users have access to a wide variety of well-established applications that are compatible with Unix, MS-DOS and CP/M operating systems. Both Meridian SL and DV-1 systems permit a wide range of other computers to be connected through the system.

Among the new terminals is a unit that combines a computer terminal with a fully featured telephone, providing a single point of access to the services offered by the Meridian SL and DV-1 systems. The Meridian M4020 terminal includes an adjustable screen with scrolling and window features, hands-free telephone service and a movable keyboard. Its 2.56-Mb/s connection permits rapid handling of large amounts of information. The Meridian M2000 digital telephone sets offer simultaneous digital voice and data transmission at speeds to 19.2 kb/s over standard telephone wiring, while the Meridian M3000 Touchphone is a sophisticated digital telephone with a touch-sensitive liquid-crystal display that replaces all the buttons. The display is programmed to guide users through the full line of integrated voice and data features available on the Meridian SL systems.

At the TCA show in September, Northern Telecom expanded the applications of Lanstar by adding Ethernet-to-Ethernet and terminal-to-Ethernet communications, as well as coax elimination and switching-system support of IBM 3270 PCs and color terminals. Lanstar also supports the CPI interface, an X.25 gateway and emulation for IBM PCs and 3270 displays.

GTE Communication Adds Packet Transport

GTE Communication Systems also used the TCA show to announce enhancements to its Omni SII and SIII PBXs. Packet data switching is now available on the PBXs, offering simultaneous and direct connection for 255 terminal users to a single host or public data port. The Omni PD-200 packet data transport system includes packet managers for asynchronous equipment at speeds to 19.2 kb/s and X.25 synchronous devices at speeds to 64 kb/s.

The Asynchronous Packet Manager (APM) provides users with complete X.3 packet assembler/disassembler (PAD) functions at their desks. The resulting X.25 packets are then converted to GTE's proprietary Mini Packet Protocol to transmit to the Omni series PBX. A telephone can be placed directly on the APM to save desk space. The Synchronous Packet Manager (SPM) features a dual-bus architecture to ensure that all data users have access to an open path to a host computer at all times. The direct virtual connection eliminates the need for the costly port contention devices required to connect many other PBX systems to the data network or computer host.

High-speed voice and data are transmitted over standard twisted-pair wiring. Dynamic bandwidth allocation eliminates the need to dedicate voice-switching paths to data, because each switch path has access to over 1-Mb/s bandwidth that's allocated on a demand assignment basis. This reduces the number of ports required and eliminates multiplexers and concentrators.

GTEhs Omni SII and SIII systems can handle up to 1,024 and 2,048 telephone lines, respectively. The packet data transport system provides connections for up to 240 data users. In 1986, th is capacity will be expanded to support more than 1,000 data users, according to the company. GTE has also introduced a retrofit package for existing GTD-1000 and early-version Omni SII PBXs, doubling their line-size capacity to the 2,048 ports supported by Omni SIII. The retrofit package also makes available the expanded feature capabilities of the Omni SIII, including those relating to packet and circuit-switched data, digital feature-phones, networking, voice messaging and the expanded maintenance and customer administration features.

For smaller businesses, GTE has improved the circuit-switching capabilities of its Omni SI PBX to permit the simultaneous transmission of voice and asynchronous data at speeds to 19.2 kb/s over a single twisted-pair telephone wire. Data is transmitted through the firm's digital intergrated featurephones, the FeatureComm V and VI, that provide one-button access to Omni system features. The Omni SI can handle up to 256 voice and data ports and typically serves businesses with between 30 and 200 telephone users.

ITT Targes the Office-Automation Markets

At the TCA show, ITT Corporation announced several developments aimed at increasing its penetration of the communications and office-automation markets. ITT's Raleigh, North Carolina-based Business and Consumer Communications Division (B&CCe announced expansion of the System 3100 digital PBX from the current port capacity of 288 ports to a capacity of 384 ports, with delivery scheduled for next July. A subsequent upgrade will double the size of the System 3100 to 576 ports. It also announced a computer-controlled automatic call-distribution system and a call-accounting software package that runs on the System 3100 and ITT Xtra personal computer.

In addition, ITT B&CC joined with ITT Courier Terminal Systems of Tempe, ARizona, to unveil an applications processor designed to provide an array of office communications functions. Working with the System 3100, the applications processor will provide file service, file transfer, 3270 emulation, X.25 support, electronic mail and call accounting in its first release. Scheduled to be available from ITT B&CC next fall, the applications processor will connect to the System 3100 with an RS-232 device so that as many as eight users can be connected simultaneously. The product gives terminal users the option of communicating on-line with the 3270 host computer, or accessing the local power of the ITT applications processor. This local power can provide office productivity tools such as word processing, spreadsheet analysis and electronic mail to users of 3270 display terminals.

The System 3100 provides simultaneous voice and asynchronous data transmission at speeds to 19.2 kb/s, with speed and format conversion and automatic data call setup. A fully modular, microprocessor-based distributed-architecture system, the PBX begins at 40 ports and grows incrementally through the addition of stackable modules to 288 ports, or 384 ports in the expanded version.

In September, ITT Announced the formation of a new business organization, the ITT Business Systems Group, to manufacture and market its telephone systems and information systems products. The move brings together four ITT units with combined annual revenues of about $800 million. They are ITT B&CC, ITT Courier Terminal Systems, Qume Corporation of San Jose, California, which manufactures computer printers, display terminals and memory products, and ITT Information Systems of San Jose, which manufactures the ITT Xtra line of personal computers.

Foreign Firms Take Aim on Digital-PBX Dollars

A number of foreign firms are also vying for the digital-PBX dollar. Siemens offers a data-communications feature package called Office Communications II (OCII) that uses the nonblocking, data-transparent architecture of the Saturn PBX system to provide direct digital switched communications between data devices of diverse information systems. OCII supports rates to 19.2 kb/s and allows the Saturn system to handle data and voice communications simultaneously or alternately. It also offers three digital electronic telephones available in 10, 16 or 26-button models. A 16-character alphanumeric liquid-crystal display is provided on a unit to furnish information about a call or feature.

Ericsson uses a fully distributed star/star architecture with its MD 110 digital PBX to avoid reliance on a central switch and processor. Instead, it utilizes up to 124 Line Interface Modules (LIMs), each of which can perform all the required tasks of the PBX. Each LIM acts independently, but they also act together as a unified system. The system expands from a single module of up to 200 lines to one serving more than 12,000 users with workstations and phones.

NEC Telephones has also had considerable success with its NEAX 2400 information management system, which ranges in capacity from about 184 ports to more than 20,000. Station users can perform simultaneous voice and data transmission at speeds to 56 kb/s over two-pair wiring without modems. The system also provides a wide range of integrated information services, including voice and text mail, packet switching, protocol conversion and facsimile.

In August, the Melville, New York, firm introduced the Dterm Executive Terminal, a compact unit comprising a telephone handset, dashboard, CRT and detachable keyboard. Used in conjunction with the NEAX 2400, it gives users the ability to communicate with mainframes and public data base as well as with each other.

At the TCA show, NEC Telephones announced the joint compatibility testing of Wang equipment with its NEAX 2400 and the successful linking of the PBX with a Corvus Systems Omninet local-area network. It also demonstrated value-added modules for the NEAX 2400, including store-and-forward services for nonsimultaneous communications of voice, text and facsimile mail, packet switching and IBM 3270 emulation.

Voice mail allows users to forward calls to their mailboxes when they are not available or do not wish to be disturbed. Text mail speeds creation of memos and allows communications between dissimilar terminals, while facsimile mail permits the unattended, speedy transfer of documents both during and after business hours. The packet-switching module's protocol conversion allows different types of terminals to "talk" to one another, while its network-access service links the user to public packet-switching networks. With its protocol conversion ability, the 3270 emulator module allows personal computers, CRTs and other terminals to be plugged into the Dterm telephones to communicate with the IBM host as if there were 3270 terminals.

Several multiplexer suppliers also offer dat PBXs as part of their product families. Codex was one of the first with its IMS 7800 data PBX that can support up to 246 simultaneous connections of various speeds and data formats. It allows users from a single terminal to select from a number of different hosts or from applications residing in the same hosts. If all ports are busy, users are placed in a queue and receive queue position updates until a port becomes available.

The IMS 7800 operator may define which ports or groups of ports a user is eligible to select. As conditions warrant, the operator may reassign users to different resource classes. Any terminal may be prevented from gaining access to certain resource classes, and these restrictions may be independently defined for each terminal port. Asynchronous ports are supported at speeds to 9.6 kb/s, and synchronous ports to 19.2 kb/s.

Case Communications features port switching and contention in its DCX 850 multiplexer, creating up to 64,000 network ports and up to 256 contention groups. For IBM Bisync applications, the firm provides an integral protocol converter, called Bluegate, that fits in a single card slot in the DCX 850 frame. Each card supports up to 32 network users, concentrating them onto a single link at speeds to 9.6 kb/s. Up to 10 Bluegates can be located in one frame. Bluegate emulates an IBM 3271/3274 cluster controller, making asynchronous ASCII terminals look like IBM 3277/3278 terminals. The firm also offers a reverse protocol converter, called A-Net, that allows an IBM 3270 terminal to emulate an asynchronous device. Another card, called Xgate, provides access to X.25 networks and host services for up to 64 DCX 850 users over a single composite link.

Micom's compact Instanet6000 data PBX forms the hub of a cost-effective network for terminal and personal-computer users who need to switch among shared computing resources. The device also functions as a fallback switch, routing users to alternate hosts if their primary system is unavailable. In addition, it acts as a contention unit, letting a limited number of costly resources, such as computer ports, gateways to other networks and modem pools, serve a much larger population of users on a first-come, first-served basis.

Since the data PBX uses standard telephone wiring and connectors, installation is easy and inexpensive. Any attached device can be designated to receive or initiate calls, or to do both. Half the size of its predecessor, the Micro600 data PBX, teh Instanet6000 accommodates as many as 504 channels in a single cabinet, or 1,016 channels with a second cabinet. The nonblocking data PBX handles all possible 508 simultaneous connections, each operating at speeds to 19.2 kb/s, full duplex.

Interfaces fall into several classes: local interfaces, providing four or eight independent channels; local multiplexers, supporting as many as 128 devices over two twisted pairs; gateways, for accessing IBM SNA or Bisync networks as well as X.25 networks; and integral statistical multiplexers to link remote clusters of terminals or sets of p orts over a single phone line. All the modules plug directly into the data PBX. System administrators can use a variety of capabilities to restrict access and enforce security. Passwords can also be used. Without interfaces, the Instanet6000 is priced at $7,500. A configuration supporting 376 local terminals and ports costs $40,500, or less than $110 per attached device.

Infotron Offers Intelligent Network Exchange

Infotron's INX 4400 2ntelligent network exchange and INX 4200 network-control matrix switch provide data switching, networking, network control and local-area network capabilities. They operate at TI speeds over all facilities, and at 40 Mb/s over a newly developed fiber-optic switch bus. The INX series also includes an enhanced Contender 500 data PBX that can support up to 500 cross-connects at 9.6 kb/s. The INX 4400 is intended for large, asynchronous data PBX applications typically found in Fortune 1000 companies. The INX 4200 is targeted at service industries and others using predominantly synchronous networks, while the Contender 500 is aimed at asynchronous data PBX applications at small to medium-size companies. All three products feature an interswitch networking capability that permits multiple units to be linked into a single virtual-switch network. T1 interswitch links are available that provide high-speed connections from one switch to another.

"Up to 64 switches can be connected in any arrangement over T1 links," says James Hahn, president, "providing outstanding capabilities for combined local-area and wide-area networks." For network management and control, the firm offers a custom-tailored Advanced Network Manager for each INX product that serves as a single-point control console, providing network control and information management. In addition, the ANM uses color graphics to report critical data on system conditions. It also receives and stores such information as usage trends, channel-status reports and histories of alarm conditions.

General Datacomm's DATX Integrated Office System (IOS) permits conversion of an existing voice PBX into a combined data/voice system without needing to rewire the existing building or discard the existing voice PBX. The DATX IOS consists of a DATX 2000 and the DATX Switching System. The DATX 2000 transmission capability provides access between remote terminals and CPU, supporting asynchronous and synchronous data at speeds to 19.2 kb/s with complete transparency and integrity of the data/voice communications. The switching system provides communications links for up to 1,320 terminations, expandable in 24-channel increments from a base capacity of 360 lines.

Gandalf's PACX 2000 software-controlled distributed switching system is designed to handle the networking requirements of intelligent devices such as personal computers, word processors and other workstations. Based on a combination of advanced 16-bit microprocessor technology and fiber optics, the PACX 2000 supports asynchronous data rates to 19.2 kb/s. It is transparent to data speed and code and allocates switching capacity on demand.
COPYRIGHT 1985 Nelson Publishing
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Copyright 1985 Gale, Cengage Learning. All rights reserved.

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Author:Edwards, Morris
Publication:Communications News
Date:Dec 1, 1985
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