Digital PBXs Zero in on the Key Role as Hub of Office.
Meanwhile, new firms such as Ztel and CXC have brought to market their "fourth-generation" systems that successfully marry the complementary functions of local-area networks and digital PBXs needed for tomorrow's automated office. Not to be outdone, third-generation proponenets such as InteCom have already moved to accommodate local-area networks and integrate them into their PBX architectures. Further, a number of major foreign firms, including NEC America, Siemens and Ericsson have been successful selling their systems to US firms implementing office automation systems. Fourth Generation Comes of Age
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. Up to 1500 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 just a few voice and data terminals to serve up to 20,000 users.
SPUs contain subsystems that perform applications processing such as least-cost routing, switch processing and data conversion. Most SPU contain all three subsystems, but in some cases an entire SPU may bededicated to performing applications such as data or word processing.
SPUs are interconnected via two types of rings: circuit rings, which carry all voice traffic and data at speeds to 56 kb/s; and the integral token-ring local-area network, which is compatible with the IEEE 802.5 draft standard foir token-passing ring networks and with the IBM Cabling System. Voice traffic travels at 64 kb/s on the circuit rings, which can each support 11o 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.
To go with its PBX, Ztel offers three all-digital telephones. Two of the sets have separate user-initiated feature buttons, retaining familiar key-set capabilities and providing 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.
In October, the PNX completed a successful Beta test at the Wilmington, Massachusetts headquarters of Compugraphic. "The PNX was wheeled in on a Monday and cut over on a Friday," says Dave Curreri, Compugraphic's telecommunications operations supervisor. "It was easily the smoothest cutover I've ever experienced."
The Compugraphic PNX configuration included 480 ports for support of lines and trunks, as well as over 200 of the Z/28 full-feature telsets. The Data Adapter option on the Z/28 allows users to connect terminals, personal computers, workstations and most other EIA-compatible devices to the PNX. The adapter provides automatic speed conversion for these various devices. Compugraphic users also have access to Digital Equipment VAX computers via connections provided by Ztel data servers.
At the recent TCA show in San Diego, Ztel enhanced the PNX's data capabilities with an office-automation package that allows users to implement a powerful office-wide messaging system. Also included in the package is an integrated online 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.
Ztel's office-automation package was announced along with Enhanced Networking and System Control software for the ONX. Reportedly, the enhanced networking software allows a firm to easily integrate the system into existing private networks, and, in many cases, utilize the PNX's advanced capabilities to improve network performance and increase network control. By integrating the capabilities for tandem calling, least-cost networking, uniform dialing and main/satellite operation, the software package permits PNX participation in wide-area networks. The software also provides PNX users with a controlled environment for expanding single-site systems to multi-site capabilities. The system control package permits a high level of control over single and multi-site PNX installations.
CXC's Rose system integrates a digital PBX with a local-area network and provides voice store-and-forward operation as well as text messaging and mail. A single node will support up to 192 full-duplex, non-blocking ports for telephones, 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. CXC supplements its distributed design with a proprietary variable bandwidth arrangement, where the bandwidth is allocated dynamically as required by the traffic flow. A low-speed data call of up to 4.8 kb/s, for example, uses 8 kb/s; 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.
CXC has also designed a "personal teleterminal" to complement the Rose. It includes an 80-character display and a keyboard for typing in text messages, which 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 on acknowledged. Distribution lists, pre-defined speed messages and registered mail messages are available features. When the recipient of the registered message reads it, the sender is automatically notified. 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 is supported at rates to 9.6 kb/s.
Initially, the Rose LAN is implemented in two fparts: a broadband ring for voice and wideband data, and a separate Ethernet bus for packetized data and messageing. CXC explains that the interim implementation was chosen to minimize the technical risk of betting on an IEEE 802.5 token-ring standard. When the standard is finalized, CXC plans to discontinue the Ethernet bus and use it as a gateway to Ethernet-compatible networks.
The broadband ring operates at 50 Mb/s and supports circuit switching of voice and data at a combined throughput of 33 Mb/s using a CXC proprietary RF modem in standard CATV technology. The additional capacity is reserved for the future implementation of four 4-Mb/s token-ring bands that will be consistent with the IEEE 802.5 standard and IBM token-ring protocols. In the future, users will be able to extend the network further by interconnecting up to eight network rings via special bridges. Further, protocol converting gateways will be supported to connect CXC's local-area network with GTE Telenet and other wide-area network.
Reportedly, the distributed architecture of the Rose allows for smooth growth at a relatively constant price per line from a modest single-node system with up to 192 ports, to a single ring system of over 12,000 physical ports, and ultimately to a multi-ring system of over 25,000 subscribers. Also, the architecture guarantees system reliability and integrity. An failure is localized in the area where it occurs, so the rest of the system continues to function without disruption. InteCom Joins With Wang Labs
InteCom, which launched the thirdgeneration PBX with its Integrated Business Exchange (IBM), has also integrated a local-area network within its design. Its LAN mark uses standard twisted-pair telephone wire to allow office devices to communicate with each other at burstmode 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 online 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 contain microprocessors that ute circuit-switched data, voice and packet transmissions to their different destinations. The outermost layer contains up to 32 Interface Multiplexers (IMs), which 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 VoiceData ports support either InteCom's analog handsets or the special digital units, called Integrated Terminal Equipment. 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.
InteCom also supplies a family of packet-based controllers, called InteNet, which perform the format and protocol conversions needed to allow a range of dissimilar business machines to communicate with each other via the IBM. One of the InteNet packet controllers, the 3270 IPC, allows ASCII terminals to emulate IBM 3277 devices connected to an IBM or equivalent host. An enhanced version of the IPC announced at the TCA show simultaneously supports IBM bisync and SNA protocols.
Another controller, the X.25 IPC, gives up to 16 user ports simultaneously use of a single X.25 network link for sending data and voice. The X.25 IPC also supports X.3, X.28 and X.29, with hardware and soiftware integral to the IBX performing packet assembly and disassembly. GTE Telenet, Tymnet and Uninet recently certified the IBX for use with their X.25 networks. InteCom also offers the Word Processor IPC, which allows IBM and Wang word processors to communicate with each other. The fourth member of the IPC family allows a data call to be dialed directly from a terminal without interrupting a voice call in progress.
In April, Wang Laboratories agreed to acquire up to 30 percent of InteCom and to pursue joint development and marketing projects and share technology. At the same time, the Lowell, Massachusetts firm unveiled a fourtiered PBX strategy. The first tier calls for the interfacing of Wang computers with all leading PBX systems. Level 2 calls for Wang to provide value-added services by integrating with other PBX offerings, and the third level requires Wang to work with other PBX vendors to provide full features and functions of Wang systems with their PBX offerings. The affiliation with InteCom comes into play at the fourth tier with joint development and marketing.
"What's required today is a single network that allows telephone and computer equipment to transport information with equal ease,c notes John Cunningham, Wang president. "It was with this goal in mind that Wang decided to form a strategic affiliation with InteCom." Frederick Wang, executive vice president, explains that the companies envision a PBX-to-WangNet gateway that will allow users to take advantage of the capabilities of both technologies. WangNet would be offered in applications "requiring high bandwidth," while the InteCom technology would be used for "applications requiring high levels of connectivity."
The first product to come from the joint effort, an integrated workstation, was unveiled at the recent TCA show. Targeted for delivery in mid-1985, the workstation integrates a desktop data terminal with an advanced telephone handset. Some of the planned functions for the workstation include one-button speed dialing for voice and data, least-cost routing, incoming caller identification, personal directories with automatic telephone dialing, time management, asynchronous communications terminal emulation, calculator functions and voice messaging. The workstation includes a nine-inch video screen, telephone dashboard for access to telephone, personal productivity and data functions, attachable typewriter-like keyboard for data entry, handset and built-in speakerphone. The workstation attaches to the IBX network via two-pair telephone wire and includes an RS-232 connection for an optional printer. IBM-Rolm Merger Heightens Competition
At the time, analysts were quick to compare the Wang-inteCom relationship with the IBM-Rom arrangement, whereby IBM had acquired a 23 percent stake in the Santa Clara, California firm. In September, IBM surprised the analysts by announcing its plan to pick up the remaining 77 percent in a move that heightened the competition between the world's largest computer company and AT&T.
Rolm's highly successful computer branch exchange (CBX) had already won 12 percent of the PBX market, compared with AT&T's 50 percent share. Last December, Rolm staged a live teleconference for audiences in 52 cities in the US and Canada to announce its new-generation system, the CBX II. The CBX II uses the same line and trunk interface cards as the earlier CBX. Also, the processors are software compatible with the existing product line, so all software and hardware feature capabilities, as well as applications processors for the CBX product line, are available in CBX II, including PhoneMail, Call Management Recording and interfaces to X.25 networks. In addition, the more than 13,000 existing CBX owners can readily upgrade their systems into a full CBX II.
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. Each node is independent of the others to provide high system-level reliability. A single-node system supports up to several hundred users, and the CBX II supports up to 15 nodes, for a total of more than 10,000 users. 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, non-blocking inter-node connections are provided by fiber-optic links that accommodate rates to 295 Mb/s between any two nodes in the system. Also, the new ROLMlink provides a 256-kb/s bidirectional pipeline from digital desktop devices on a single twisted pair of telephone wiring.
An integral part of the new CBX II family are three digital telephones, the new ROLMphone 120 and 240, as well as the previously announced 400. The new devices provide single-button feature access for both voice and data calls. When equipped with an optional data communications module that fits inside the phone, each provides a plug-in connection for a terminal, personal computer or other data device. AT&T Unleashes Gazelle
As for AT&T Information Systems, it has enjoyed success with the System 85 switch, which the newly deregulated subsidiary announced in January 1983 for customers with upwards of 500 lines. Last April, AT&T unveiled its System 75, the digital switch, code-named "Gazelle," that was under development for several years. Designed for installations of up to 300-plus lines, the System 75 handles voice and up to 64-kb/s data traffic simultaneously. Built-in voce capabilities include six-way conferencing for staff discussions and advanced call-management features.
The system also 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 provison for remote diagnostics and maintenance.
Another option, terminal emulation, allows AT&T 500 and 515 Business Communications Terminals to act as IBM lookalikes or standard asynchronous terminals. The System 75 will also support the 7100 and 7400 series terminal family introduced last year, and the System 85's applications processor. Software is based on Feature Package 15, with new added features, including protocol conversion software.
AT&T Information Systems has been active in opening its digital switched systems to office-automation vendors, including Data General, 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. Northern Telecom Extends OPEN World
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.
Northern Telecom has also been working with Hewlett-Packard, Sperry and Wang Labs to integrate their computers with its SL-1 digital PBX. In addition, Protocol Computers of Woodland Hills, California has developed protocol converters that allow the SL-1 to emulate an IBM SNA/SDLC cluster controller, enabling Northern Telecom's terminals and other ASCII devices supported by the SL-1 to communicate with IBM host computers.
Northern Telecom recently enhanced the data networking capabilities of the SL-1 with two gateways and an interface module that permits asynchronous and synchronous terminals to communicate with various data bases through the SL-1. The asynchronous/synchronous interface module, or ASIM, eliminates the need for different interfaces to support synchronous and asynchronous terminals and has a list price of $456. The SL-1 System 36 gateway permits integration of personal computers, printers and other ASCII terminals with IBM System 34, 36 and 38 host computers. With the gateway, SL-1 can transmit and switch data from the ASCII terminals to the IBM host computers at speeds to 9.6 kb/s. Likewise, the SL-1/X.25 gateway provides asynchronous ASCII terminals with direct digital-format access to packetswitched networks via the SL-1. SL-100 Digital PBX Enhanced
Northern Telecom has also enhanced the data-handling capabilities of its SL-100 digital PBX with support for a number of IBM communications protocols and an X.25 gateway. One feature permits switched access to IBM 3274 and 3276 controllers from IBM 3270 terminals over twisted-pair telephone wiring, eliminating the need for more-costly coaxial cable and making terminal moves less expensive. It also allows the terminal to access multiple host computers and data bases via the SL-100.
AS protocol-conversion feature permits most ASCII asynchronous terminals to operate as IBM 3178 or 3278-type on-line terminals, while another converter allows the same terminals to function as IBM System 34, 36 or 38-compatible products. Another device allows the IBM personal computer to connect to and communicate in digital format with the SL-100 via twisted-pair telephone wiring.
Along with the PBX enhancements, the firm also introduced Displayphone Plus, an integrated voice and data terminal capable of emulating devices from IBM, Digital Equipment and Data General, among others. The terminal features a fu66-size retractable keyboard and an amber screen. Its telephone unit includes a 90-number directory, automatic dialing feature and "hands-free" speaking. The terminal also contains an intrnal 212A-compatible auto-answer modem with selectable 300 or 1200-b/s transmission rates. All the products are part of Northern Telecom's $1-billion Open Protocol Enhanced Networks (OPEN) World Research and Development Program. OPEN World is the firm's commitment to accommodate most types and makes of business equipment and to permit all major office communications functions to operate on a single integrated system. Interest Builds In Shared Tenant Services
Last June, Northern Telecom announced a software package that will enable building owners to offer tenants the advantages of a fully featured digital PBX. The Enhanced MultiTenant Service offers such features as shared access to trunk routes, integrated voice and text messaging, and automatic call distribution. An SL-1 system equipped with the new software package could operate as 32 PBX systems, each with the potential to serve as many as 512 tenant groups. The package improves control, efficiency and profits by permitting communications mangers to break down billing and management reports by system, tenant organization and extension. The software will not be available until next July, but was announced a year ahead to allow for planning of new buildings.
With the software package, Northern Telecom joins a growing list of suppliers, including AT&T, InteCom and Mitel, to offer PBXs for shared tenant services, whereby a building owner purchases a switch and offers its capacity for use by business tenants.
Satellite Business Systems has also joined the fray with a subsidiary, Real-Com, formed to provide advanced communications services to real estate developers and office-building owners. The SBS subsidiary provide developers with the PBXs, telephone instruments and cabling to connect each building's tenant to local and long-distance networks. It will also contract with individual teants to provide them with turnkey communications services, equipment and features tailored to meet their requirements.
RealCom's first customer is Urban Investment and Development Company, which is planning building-wide communications systems for new complexes in Boston, Chicago, Denver and Philadelphia. In March, SBS also reached agreement with Ameritech Communications for the provision of tenant communications services in 60 major office and mixed-use real estate developments in major cities across the U.S. Under the agreement, Ameritech Communications will supply RealCom with $100 million in communications equipment and will install, maintain and administer the equipment at an additional cost of $80 million.
InteCom was one of the first to recognize the potential in multi-tenant services, which is now expected to grow into a multi-billion-dollar business during the next three years. After installing an IBX system, the Chicago Board of Trade saw an opportunity to provide groups of brokers connection to the system on a shared-tenant basis. The idea also caught on with a Dallas-based communications company, TEL-Management, that now furnishes 75 tenant groups at the Galleria Office Tower enhanced communications with an Intecom IBX system.
InteCom has since signed a $50-million agreement with LinCom Corporation, a subsidiary of Lincoln Property Company. Lincoln, one of the nation's largest real estate developers, plans to install the PBXs in nearly 40 of its office buildings and hotels during the next two years, and to offer optional communication services at a profit to businesses that rent space in a property. Amenities will include telephone switching, voice store-and-forward, messaging, data and word processing, electronic mail and telephone conferencing.
InteCom has also signed a $100-million agreement to supply IBX systems to Isacomm, the Atlanta-based subsidiary of United Telecommunications. The IBX systems will be designed to provide multi-tenant services, which will be offered through United Business Communications, a new company formed to serve developers and building owners across the country.
InteCom is also one of three vendors selected by General Electric for its new tenant-service venture. The IBX systems will be offered along with long-distance telephone service from MCI and office-automation systems from Wang Labs. GE Information Services, through its Integrated Communications Services Operation, will be the single-source provider and integrator of these various products and services for tenants in commercial office buildings.
Mitel, one of the early stars in the digital PBX firmament, lost some of its lustre when IBM pulled out of a joint venture, putting its weight instead behind Rolm. IBM's decision was thought to be based on software-related delays in the development of Mitel's SX-2000 Superswitch. At the time, the SX-2000 Superswitch was considered one of the most technically advanced PBXs available. In a typical 2000-port configuration, the SX-2000 occupies less space, uses less power and operates at a higher speed (256 kb/s) than comparable products. It has a capacity of 10,000 lines and can support local-area network interfaces, word processing, facsimile, electronic mail and host-to-host terminal links at up to 2 Mb/s. Small Systems Assume Larger PBX Features
For smaller offices, Telenova of Los Gatos, California has introduced an integrated voice-data system with many of the innovative features of the larger digital PBXs. The Telenova 1 business communications ystem consists of a central module linked over two separate highspeed buses to a series of specialized interface units (IUs). The IUs are circuit cards that interpret and pass on command messages between the module and lower-level devices and facilities, such as Telenova station sets, computers and outside trunks. Planned IUs will permit interfacing the system with LANs, T1 PCM trunks, video transission facilities and packet-switched networks.
The module incorporates an 8086 processor and up to 16M bytes of random access memory. It also houses a 5M-byte Winchester hard disk for mass storage of various system data, and a 360K-byte floppy disk, which is used for loading new software, such as program upgrades or new feature sets. The dual-bus configuration includes a transaction bus that transmits control messages in packet-switched format between the module and the various IUs, and an 18M-byte circuit bus that's divided into 256 time slots of 72 kb/s each. This bandwidth can be dynamically reallocated in increments of 8 kb/s to match the bandwidth needs of various on-line services, such as video and higher or low-speed data traffic. The station set has a two-line, 40-character display to guide the user through each step. It highlights only those services that are logical and useful at a given time. Standard telephones can also be used, if desired.
GTE's initial response to the growing demand for data capabilities was to upgrade its voice PBX with add-on modules to convert it into an integrated voice/data system capable of switching data at rates of 56 kb/s. Since then, GTE has unveiled its Omni family of integrated voice and data PBXs, which serves offices with 50 to 2000 lines. Its GTD-4600 serves up to 9200 lines, while the Omni SV can handle up to 50,000 lines. In additions, the firm markets the XT-300 Actions Station, a voice/data desktop terminal not much larger than a standard telephone, designed for managerial and supervisory personnel. The unit combines an electronic telephone with a nine-inch display monitor, keyboard and 50-number automatic dialer.
At the recent TCA show, Anderson Jacobson unveiled a modular design for its Integrated Office Exchange (IOX) that allows users to expand the system from 100 to more than 24,000 ports. The IOX System is defined by a software data base specific to each customer. Configurations, changes and upgrades may be generated locally or from a central off-site location. Its proprietary digital telsets incorporate a microporocessor for controlling telephone functions, a codec for digitizing voice signals, a memory and other circuitry for sending and receiving signals via the switch processor.
The basic unit includes eight most-used feature keys and six user-programmable keys in addition to the 12-key pad; up to 18 additional feature keys can be included in increments of six. An optional visual display provides the telset with selected voice and data messaging. The system supports both asynchronous and synchronous communications at rates to 19.2 kb/s, with provision for 64 kb/s in the future. The system also has provision for integrating local-area network and office-automation equipment in the future. Foreign Suppliers Make Inroads
A number of foreign firms are also gearing up for the upcoming battle over digital PBXs. NEC America has 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, local-area networking, packet switching, protocol conversion and facsimile.
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 (LIM), 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 firm points out that, with fully distributed processing, intelligence functions can be activated anywhere in the system that they may be needed. The Ericsson MD 110 can accommodate from 100 to 20,000 data terminals or telephone extensions in non-blocking mode.
If something should go wrong, the MD 110 monitors the problem, activate an alarm, automatically uses a reserve unit and locates the fault to within one or a few printed-circuit boards. This monitor and diagnostic function can also be performed by telephone from a remote operation center. Ericsson recently won its first major US order by signing Wells Fargo Bank to a $4.3-million contract for an MD 110 system serving 2,810 lines. The contract also covers digital telephone handsets.
At this year's ICA show, Honeywell announced that the first product to emerge from its joint venture with Ericsson will be based on the MD 110. Known as the Delta-Plex Series 2000, the system will offer speed, code and protocol conversion services to support SNA, X.25 and other popular network offerings. The Series 2000 will use module hardware and software, allowing system expansion from 100 to 12,000 lines in 200-line increments. Honeywell also plans to enter the multi-tenant services field providing building owners and developers with computer, communications and building controls equipment. Siemens Enhances Saturn PBX
Siemens recently enhanced its Saturn PBX with a data communications feature package and three new digital electronic telephones. The data package, called Office Communications II (OC II), uses the non-blocking, data-transparent architecture of the Saturn system to provide direct digital switched communications between data devices of diverse information systems. OC II supports rates to 19.2 kb/s and allows the Saturn system to handle data and voice communications simultaneously or alternately. The three new telephones (Digital Premium Instruments) are grouped under the name DPI II, and are available in 10, 16 or 26-button models. A 16-character alphanumeric liquid crystal display is provided on each DPI to provide information about a call or feature.
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|Date:||Dec 1, 1984|
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