Software Review - Vision 100 VT100/220 Terminal Emulator

by Jon Calvert

VISION 100 is a terminal emulator for the Z88 based on the Digital Equipment Corporation (DEC) VT100 video terminal standard and is written entirely in Z80 assembler. The software is produced by Ranger Computers Ltd of Northampton, and is currently supplied on a 32k EPROM accompanied by an A4 sized 41 page manual. Ranger combine the Z88 and VISION as a package, aimed mainly at the corporate market where a one piece solution is required, but VISION can be supplied separately for existing Z88 owners.

The manual is clearly printed and illustrates both the commands and Escape codes expected by VISION to perform its tasks. A usefull section on cable wiring is included to help eliminate potential problems in connecting the Z88 to a host computer system either directly or via a modem - a point which some terminal emulator manuals fail to help with at all!

Plugging software into the Z88 always fills me with intrepidation. Will it prove to be a package that needs a hard reset to get over the odd bug? Brrr! always makes me shudder, and so a full backup of the Z88 is always performed before doing it. With VISION though there was no need to worry. The package performed faultlessly.

Selecting VISION from the Index or []ZV, brings up the VISION intro screen, or your suspended session, whichever is appropriate. The left side of the display indicates the current communication settings i.e. the transmit, receive speed and number of bits per character. The right side of the display holds the 80 by 24 line map display and some other informational displays such as indicators for CLI, CTL, and APPLICATION modes. The centre portion of the display is devoted to an 80 by 8 line window onto the full 80 by 24 line screen display which can be scrolled up and down using the SHIFT arrow or Diamond arrow keys as in PipeDream.

The menu key provides normal Z88 style menus for easy access to features such as the VISION file transfer options or the terminal SETUP screens, but pressing the [] key will really impress you. Instead of popping up a square symbol on the right side of the screen, the whole screen is cleared and is replaced by a visual display of the Z88 keyboard and its mapping to the VT100/220 keyboard.

The next key that you press (providing it is one on the display), is translated by VISION into its corresponding VT100/220 key sequence. This means that []5 will be translated by VISION into the BREAK key sequence, or []Y will generate the DO sequence on the VT220 keyboard. It might sound odd reading this, but using it is absolutely incredible. It's fast, slick and other software developers should start queuing up now to find out how they do it!

Using the square key in this manner does mean it is slightly more difficult to get back to PIPEDREAM or pop-ups (you have to via the INDEX key), but if you consider that the Z88 has a distinct lack of extra keys to facilitate VT220 emulation, then this method of operation is a godsend.

The other major extra keys on the VT series terminals are the PF keys 1 through 4 and the numeric or application keypad. Here the VISION invocation is more direct. Diamond 1 to 4 emulates the appropriate PF key, and pressing Diamond ENTER raises the APPLICATION symbol at the right side of the display and swaps the number keys 0 to 9 and the ENTER key to application mode.

Anyway, having got through the descriptions of keyboard manipulation, how do you map a 24 line screen onto an 8 line display? The answer is very effectively. Two modes of operation have been allowed. The first mode and probably the most common, is for the display to reflect the current cursor position. The display shows the third of the screen containing the cursor at all times. The alternative is that a particular third of the screen is constantly displayed. This mode is very useful for things such as the 2020 spreadsheet, where you want the display to remain on the active slot, and not skip back to the command line during things such as formatting operations. The screen mode operation can be changed at any time though by summoning the SETUP Z screen and amending the Move Window option.

VISION has another nice feature in SETUPs. If you amend any of the defaults from the SETUP menus A,B or Z, VISION retains the amendments in file in :RAM.0 called VISION2.CNF. Even if you then remove VISION from the machine, the file remains and the next time you replace and load VISION, your defaults are automatically loaded and set.

Connecting the Z88 to a VAX and running some standard software to evaluate the package was very rewarding. I was unsure how useful an 8 line display would be with facilities such as the VAX operating system MONITOR display which illustrates system usage, but VISION was remarkably good.

Locking the screen into one section allowed a particular panel to be displayed, and the line graphic character animations used in the display showed the performance bar charts as well as any VT series terminal. Terminal speeds of 9600 Baud proved to be no problem in keeping the display updated with characters or attributes such as reverse video.

Function keys and Application keypad conversions work exactly as they should, and control keys can easily be sent by using the Diamond followed by the key required (a CTL symbol pops up at the right hand side of the screen when the Diamond is pressed), but for those used to using a VT terminal, it is just like using the CTRL key.

Using the SET TERMINAL/INQUIRE command under VAX/VMS even works, allowing the VAX to detect what mode you have set VISION to, VT100, VT102 and 7 or 8 bit VT220.

So who needs a Z88 with a terminal emulator? Well I do for one! I spend a lot of my time using VAXes, and anyone with a mobile requirement for uploading and downloading information between the Z88 and other machines that support ANSI or VT100 terminals will benefit from using VISION 100 (no more .J editing of text files using the low-tech VT52 emulator built into the Z88). Other professionals that spring to mind are Journalists, System Managers with multiple sites, Sales Representatives and even students.

The total cost of the Z88 and VISION 100 is less than £400 at current prices, and for a portable terminal with local processing power, that represents excellent value for money.

Ranger are currently in the process of upgrading VISION to include features such as the KERMIT file transfer protocol and some modifications to the way that the APPLICATION keypad mode is used. This will mean a move to a 128k EPROM as opposed to the 32k that the current version is squeezed into, and unfortunately a corresponding rise in price from its current £175. There may be some other features included, but evidently we will ahve to wait and see what the future brings.

One thing that Ranger do have is a split comms cable. If you use the Z88 in the office and also have a VT type terminal on your desk, the split cable allows you to use the Z88 as your keyboard/Z88 but with the advantage that the terminal shows the normal screen output from the host machine. Really neat! So far they have used the cable for development purposes, but they may be persuaded to make one for you...

In conclusion, the VISION software allows the Z88 to be attached to almost any system and send and receive files easily. It performs very well as a good VT series emulator, and though the price in Z88 software terms may make you wince personally, for anyone who needs VT emulation with portability it represents excellent value for money.

The VISION 100 Terminal Emulator is priced at £175 + £3.50 postage. It is available from:

Ranger Computers Ltd, The Innovation Centre, Boughton Green Road, Moulton Park, Northampton. NN2 7AH. Tel: 0604 791064.

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