Terminals FAQ

Suggestions for questions and answers are welcomed.

Where can I get answers to my terminals questions?

If you have access to newsgroups, try comp.terminals. There is no official FAQ for the group, so if your question isn't answered by this document, jump right in!

The most comprehensive Web site of information for all makes of terminal is Richard Shuford's archive of Video Terminal Information.

Where are terminals used, today?

In the 70s and early 80s, computers were mainly contained in climate-controlled rooms that only operators had access to. Users sat in front of terminals, which were text-only or graphical devices with no local storage, so there was very little opportunity to mess up your machine. You couldn't install software and you couldn't catch viruses. Updates to software were applied infrequently and carefully, by the operators.

In the 80s, computing power moved onto people's desks in the form of PCs and workstations, letting loose all the dangers of incompatible set-ups and unmanaged software installation. Terminals started disappearing, except in specialised applications such as point-of-sale (POS) and monitoring equipment.

Today's buzzword is "thin client", where software management has been taken back into the server room, and users have something like a "light PC" on their desks. There is typically more computing power and better graphics available than twenty years ago, but the management cost and cost per desk has reduced (apparently). Many of the old text terminal vendors have repositioned themselves in this market (e.g. TeleVideo, Wyse and Boundless), while others have got out of the business or disappeared altogether (Lear Siegler, Volker-Craig).

However, you can still buy text terminals, and they still have a use in applications where you'd like to have multiple users on one machine, cheaply, as console for your Linux / BSD / VAX / take-your-pick box at home, or for monitoring equipment, in embedded systems development.

Where can I buy terminals?

You can still buy text terminals from the vendors mentioned above, but you'll find that new prices are pretty steep for home use. So, where can you buy them second-hand? Well, the options vary depending on where you are. In the United States there seem to be many more hobbyist technical or junk stores around than in the United Kingdom. Computer Fairs generally cater for the PC market, so they're no good, but fairs for radio amateurs, called "Hamfests" in the U.S. and "Radio Rallies" in the U.K., are the place to find a variety of old computing equipment, much to the annoyance of some.

The American Radio Relay League has a schedule of hamfests in the U.S., at http://www.arrl.org/hamfests.html.

The Radio Society of Great Britain Web site, at http://www.rsgb.org.uk, has news of radio rallies.

Terminals also turn up for auction on eBay and eBay UK, in the "Computers & Games : Hardware : Terminals" section.

How do I connect a terminal to my PC?

If you're running Linux, or another variant of Unix, take a look at David Lawyer's comprehensive Text Terminal HOWTO. It explains fundamentals of serial communications, choice of cables, Terminfo and setting up specific terminals.

For MS Windows, take a look at STerm. Microsoft's own Windows Terminal Server is nothing to do with text terminals; it talks to the "thin clients" mentioned above.

Where can I get a list of VT100 or ANSI escape codes?

These are two frequently-confused terms. "ANSI" either refers to:

X3.64 defines a whole family of capabilities and the means of invoking them, not all of which are appropriate to text terminals. ANSI.SYS implements a subset of these capabilities, and adds some private extensions, allowed for within X3.64.

Although "VT100" is a model of terminal previously manufacturered by Digital, it nowadays is most often seen as a setting in terminal emulators. In this case, it normally means that the emulator will respond to escape sequences in the same way as a real VT102 terminal, the VT100's slightly more capable brother.

So, the definitive place to find a list of VT100 escape codes is the VT100 User Guide. The VT102 escape codes are in the VT102 User Guide.

Confusingly, many pages on the Web which claim to list VT100 escape codes, really list codes supported by a particular terminal emulator, or they list the codes supported by ANSI.SYS. If you find a list and it claims that the sequence ESC[s saves the cursor position, you're looking at a list for something based on ANSI.SYS, not the VT100.

How about escape codes for Wyse, TeleVideo, etc.?

Although many Wyse terminals emulate ANSI-compatible terminals, they also have a proprietary native language. Although Wyse have just rearranged their Web site (and broken sections of it), you should be able to find escape codes in the Knowledge Base.

TeleVideo don't have any information about old text terminals on their Web site, but Richard Shuford's site contains lists of control codes, on the TeleVideo page.

How do I get my VT510/VT520/VT525 into Setup?

If you've got a VT keyboard, press F3. If you've got a PC keyboard, hold down Caps Lock and press Print Screen.

Here is the section from the DEClaser 5100 Printer User's Guide:

Locking the Set-Up Menu Configuration

The Set-Up Menu lock feature is designed to prevent casual or accidental modification to the state of the DEClaser 5100 printer. To prevent users from modifying the state of the printer, use the following procedure.

  1. Press OnLine to pause the printer.
  2. Press Set-Up to enter the Set-Up Menu.
  3. Choose the Miscellaneous sub-menu.
  4. Choose the Set-Up Menu lock feature.
  5. Choose LOCK=enabled.
  6. Press Enter to select the value.
  7. Press * to confirm and save the lock enable feature.
  8. Press OnLine to return the printer online.

When the Set-Up Menu lock feature is enabled, attempting to enter the Set-Up Menu by pressing Set-Up or the Reset Menu by pressing Reset sounds the beeper and the message "Set-Up locked" appears for 2 seconds.

When the menu is locked, the Set-Up menu features can only be modified by using host commands. You can configure the Default feeder feature in the Feeders sub-menu from the Feeder Select Menu.

When the Set-Up Menu lock feature is enabled, you can access the Set-Up Menu using the following procedure:

  1. Press OnLine to pause the printer.
  2. Press and hold *.
  3. Press and release Set-Up.
  4. Release *.

The message Set-Up Menu appears and the printer is now in the Menu state.

NOTE: If you exit this menu without disabling Set-Up Menu lock (LOCK=disabled), the Set-Up Menu will remain locked.

Credits. The following people have contributed (possibly unwittingly!) to this FAQ: Tim Fraser (ARRL link).