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Mainframe terminal emulation on a PC.

Mainframe terminal emulation on a PC The ability to communicate between a PC and a mainframe system has several advantages. The first is to have a single unit serve a dual purpose, so that the PC becomes both a terminal connected to the mainframe and a stand-alone for running MS-DOS applications. Second is to conserve space by not needing two keyboards and monitors in the same work area.

A third advantage is being able to capture files from the mainframe and send the output to the printer connected to the PC or to be stored in the PC's disk drive. A mainframe file captured on a PC diskette can later be used on the PC for word processing, spreadsheet, or database applications. You can download a text file or ASCII report from your LIS mainframe, for example, and print it out or keep it on hand in your PC for review or updating.

Emulators are applications run on MS-DOS PCs that allow the PC monitor and keyboard to function like a CRT connected to the mainframe. The emulation application connects to the mainframe via the PC serial port to a port or address on the mainframe system. Most communication programs include some type of emulation that is compatible with common terminals, such as the DEC hardware and VT-100 terminals often used in hospitals.

At our laboratory, we use a product called The Impersonator (Direct Aid, Boulder, Colo.), which lists for $250 but can be purchased from many discount suppliers for less. The Impersonator (IMP) can emulate at least 16 asyncronous terminals, of which the most common programs are listed in Figure I. I have found the company to be highly cooperative; they're even willing to consider adding new programs on request.

The file, downloaded to a PC diskette, will be in ASCII data. It can be converted to other formats by means of an MS-DOS application called One-Shot (Data-Viz, Trumbull, Conn.), which lists for $195. One-Shot will take the downloaded file and allow the user to define each line as "data," "leader" (header), or "skip" (delete). The user defines each column and saves the file as a text (.DOC), spreadsheet (.WKS), or database (.DBF). Saving templates allows speedy conversion of similar files containing different data.

* Downloading. Like any mainframe system, our LIS generates lots of reports. In some cases a user may want to manipulate information from the report in a word processing or graphics application. Being able to download the report to a PC disk file and work on it immediately eliminates the time-consuming and error-producing step of reentering data.

Our supervisors use the LIS's office automation (OA) module for preparing memos, procedures, articles for outside publication, and so on. Occasionally a supervisor wants to download a file created in the OA module to be used on a PC for word processing or graphics. It was just such a project that inspired us to devise the method described in this article. One of our supervisors had written "On-Line Laboratory Section Budgeting" (MLO, February 1990) on the mainframe. The editor of this column asked her for a diskette. At around the same time, the microbiology supervisor expressed an interest in capturing information from a lab report to display on a PC for conversion into slides for a program he had to present.

These and other requests galvanized us into action. By spending $250 on software (The Impersonator), we were able to "fool" our system--making the office automation module think our PC was a printer--into providing what we needed.

* How it works. We use MediTech (Medical Information Technology, Inc., Westwood, Mass.) LAB/MIC module software on a Data General MV10000 mainframe. Each section supervisor has a CRT that is linked to the LAB/MIC module and to the MediTech Office Automation Module. The CRTs connected with the Data General MV10000 are made by Esprit Systems, Inc. (San Jose, Calif.), and use a Hazeltine emulation, the only type that works with the Meditech Operating System. The lab PC is linked to the MV10000 via a serial port.

In our case, The Impersonator allows the PC to emulate a Hazeltine terminal. IMP has features of its own that are controlled by the <ALT> function key followed by a letter of the alphabet (see Figure II). One helpful feature of IMP is its ability to capture ASCII text transmitted to a PC from the host and write it to a diskette in the PC disk drive.

The MediTech LAB/MIC module can scroll reports to the screen. When the PRINT ON? prompt appears, the user enters "s" (for "scope"). Essentially, the CRT is treated like a printer as the system displays the report line by line with a carriage return/line feed (cr/lf) after each line. This simplifies the downloading of a report from the LAB/MIC module: We name the file to be captured (Figure III), then turn the IMP capture feature on and off just before and after the report scrolls. The procedure for downloading from the LAB/MIC module appears in Figure IV.

The MediTech OA module cannot, however, scroll a text file on a CRT line by line with cr/lf after each line. It allows the user to view a file only one screen at a time, boxed in with a header and a bottom line of options. When The Impersonator is used on the PC to capture the OA file, the end result is not a pretty sight. Because the OA module uses Hazeltine escape sequences to permit viewing the file, the file captured to disk is a scrambled mess that includes the header and option lines displayed on the screen.

Getting around this problem requires setting up the OA terminal configuration to which the PC is connected and using it as a printer. The IMP program is booted up on the PC, but the user names the file to be captured and turns on the capture mode without signing on to the MediTech OA module. Then, using a second CRT connected to the MediTech OA module, the user calls up the text file to be downloaded and prints it to the port to which the PC is connected. The file from the OA module will scroll on the PC monitor and be captured to disk. After the scrolling stops, the IMP capture mode is turned off. Figure V summarizes the downloading procedure from the OA module.

The procedures that are described in this article are specific for downloading from a MediTech System to an IBM or compatible PC using The Impersonator emulation software. Because IMP can emulate many different asyncronous terminals on a PC, however, this type of downloading is not limited to MediTech. Other types of emulation software can also run on IBM or compatible PCs. Other emulations for PCs have some sort of text-capturing capabilities. The exact method may vary, but the processes are basically similar.

Our lab secretary, for example, uses an IBM PC connected to the hospital information system, a Unisys mainframe. Her PC uses a syncronous emulation software package called The Perfect Mate (Intercomputer Communications Corp., Cincinnati, Ohio; $295 list). One helpful feature of this emulation package is its ability to route data to a disk file. Thus the secretary avoids the inconvenience of having another CRT on her desk and can download as desired.

Caution: If you want to obtain an emulation package for a Unisys system, ask your institution's data processing department for assistance. Some Unisys systems use an interface called TDI (two-line direct interface), which requires a conversion box.

* Applications. Terminal emulation has become a popular LIS function in our lab. Supervisors download files of lab procedures and policies, save them on disk, and edit them later on word processing software. Some lab files that used to occupy substantial space in filing cabinets are now saved on disk and printed out only when needed. These include specimen master logs and quality control and infection control reports.

I have been able to download workload and turnaround time reports to give to our management engineering department for conversion to Lotus 1-2-3 for productivity analysis. The financial people and others can obtain extensive data on DRGs with a few simple manipulations (Figure VI).

And yes, our microbiology supervisor was able to download the patient data he needed. He plugged the information into a graphics application, converted the results to color slides, and had prints blown up into beautiful charts. His presentation was a big success--thanks in part to mainframe terminal emulation.

The author is LIS coordinator, Selby Laboratory, Sarasota Memorial Hospital, Sarasota, Fla.
COPYRIGHT 1990 Nelson Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1990 Gale, Cengage Learning. All rights reserved.

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Author:Collins, Stuart
Publication:Medical Laboratory Observer
Date:Aug 1, 1990
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