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09 - Printing via a Terminal (and RetroTerm)

This document answers three related questions:

  1. When a printer has file name PRINTER and sits "on a serial port," is that a special device or a reused terminal line? (Answer: a reused terminal line.)
  2. How does printing "via a terminal" physically work?
  3. How would you enable it in a terminal emulator such as RetroTerm (which speaks telnet to an ND-100 and emulates a Tandberg TDV 2200)?

Sources: ../../Operations/SINTRAN/ND-30.003.007 EN SINTRAN III System Supervisor.md (sections 2.4.5-2.4.7, 5.6.2, 6.2.1, appendix K.6, and the terminal-type table); ../../Reference-Manuals/SINTRAN-COMMANDS-REFERENCE.md.

Where an exact byte-level detail is needed but not present in these manuals, it is marked UNVERIFIED with a note on where to get it. This document does not invent escape sequences.

1. Two distinct ways a printer relates to a terminal line

There are two physically different arrangements, and they need different handling in an emulator. Keep them separate:

Arrangement A - printer on its OWN terminal line

The printer is wired to a dedicated async serial line. No terminal shares it. SINTRAN treats that line's logical device as the PRINTER peripheral, and the line's normal login/background process is turned off so nothing competes for it. Everything SINTRAN sends down that line is the raw print stream.

Arrangement B - printer hangs off a real terminal (auxiliary printer port)

The printer (e.g. an EPSON LX-80/RX-80) is plugged into the auxiliary printer port on the back of a Tandberg terminal. The terminal and the printer share one serial line to the host. The host sends data to the terminal; the terminal, when told to, passes the characters through to its printer port instead of (or as well as) showing them on screen. This is the classic "screen dump / local print" arrangement.

System Supervisor appendix K.6 (Figure 63 "EPSON LX-80 printer connected to Tandberg terminal") is exactly Arrangement B. Section 2.4.7 (EPSON RX/80) notes the printer "may be connected to its own terminal line or to a Tandberg terminal" - i.e. either arrangement.

2. Host-side (SINTRAN) setup - common to both arrangements

Whichever arrangement, the ND-100 side is configured the same way: bind a spooling index to the line's logical device number, disable the login process on that line, and create the peripheral/spooling files.

From the System Supervisor manual, the worked example "connecting a printer to a terminal line" (terminal line 36):

@SINTRAN-SERVICE-PROGRAM

*SET-SPOOLING-DEVICE-NUMBER 1,36 Y Y Y      ; spooling index 1 -> logical device 36
*CHANGE-DATAFIELD 36 I Y Y Y                ; set the line's parameters
   TSPEED/ 000210 000210 000210 273d        ; set speed (this example = 1200 BPS)

Notes (verified):

  • *SET-SPOOLING-DEVICE-NUMBER <spooling index>,<logical device number> Y Y Y binds the spooler to the line and (per the manual) means you do not also have to remove the background program - the three Y answers write the change to memory, image, and save-area so it survives cold start.
  • If instead you set the printer up without SET-SPOOLING-DEVICE-NUMBER, you must disable the login process yourself: *REMOVE-FROM-BACKGROUND-TABLE <logical device number> Y Y Y. To give the line back to an ordinary terminal later, use *INSERT-IN-BACKGROUND-TABLE.
  • Printers with a special interface (the DMA/parallel/serial line-printer types) must take the lowest spooling indexes, sorted ascending; printers on a terminal line follow after, in any order (manual note).
  • Then create the peripheral file and spooling files on user SYSTEM (user RT must be friend of SYSTEM with access RWA), exactly as in 03-CONFIGURATION.md.

After this, PRINTER (or whatever name you bind) is a normal spooled device: @START-SPOOLING PRINTER, users @COPY-FILE PRINTER,file, etc. (docs 04/05).

3. Arrangement B extras - telling SINTRAN "EPSON shares a Tandberg line"

When the printer shares the line with a Tandberg terminal, SINTRAN must be told, so it uses the right flow control. From appendix K.6:

*CHANGE-DATAFIELD <logical device number> I Y
   TINFO/  xxxxxx  20!        ; "Epson & terminal" - include this in LOAD-MODE
   DFLAG/  xxxxxx  1000J      ; XON/XOFF on input

And the printer section of the Tandberg terminal's own communication menu must be set to match:

Tandberg printer menu item Value
Printer handshake XON/XOFF (use DTR if it is an RX-80)
Printer code format 7even (7-bit, even parity)
Printer speed 9600

(For a printer on its own line, appendix K also shows the line's own menu with "Printer Handshake: Off - To be set if local printer is used", "Printer Code Format: 7even", "Printer Speed: 9600".)

Two useful terminal-local features the manual documents for Arrangement B:

  • CTRL + PRINT dumps the current screen picture to the printer.
  • Setting "Printer Mode" = "Log" in the terminal's Function Switches menu makes the terminal log all input-from and output-to the terminal onto the printer (a hardcopy session log).

4. Which Tandberg terminal type to declare to SINTRAN

RetroTerm emulates a TDV 2200. On the ND side, tell SINTRAN what the terminal is with @SET-TERMINAL-TYPE <type>. Relevant Tandberg codes from the System Supervisor terminal-type table:

Type code (decimal) Terminal
54 Tandberg TDV2200-Standard
53 Tandberg TDV2200/9-ND-NOTIS
55 Tandberg TDV2200/9-ND-TET
80 Tandberg TDV2200/9-ND-NET
83 Tandberg TDV2200/9-V2-ND-NOTIS
90 Tandberg TDV2200/9S-ND-NET
93 Tandberg TDV2200/9S-ND-NOTIS

Pick the plain 54 (TDV2200-Standard) unless RetroTerm implements the NOTIS/TET/NET extensions, in which case match the closest variant. The terminal type governs how SINTRAN treats screen control, VDU flag, etc. (a per-terminal DFLAG word carries options such as XON/XOFF-on-input, bit values documented in the same manual).

5. Enabling terminal printing in RetroTerm - two implementation paths

RetroTerm is the terminal in this picture. How you support printing depends on which arrangement you emulate.

Path A (recommended, fully specified) - dedicated printer line

Emulate Arrangement A: dedicate one telnet connection / line as the PRINTER.

  • On the ND-100, configure that line's logical device as PRINTER with the section-2 commands and disable its background/login process.
  • In RetroTerm (or a tiny companion socket client), open that line and treat everything the host sends as the raw print stream - do not interpret it as screen output. Write it straight to a file / spool it to the host OS printer / render to PDF. Honour the flow control you configured (XON/XOFF, or just read as fast as you can).
  • The host drives it as an ordinary spooled printer: @START-SPOOLING PRINTER then @COPY-FILE PRINTER,file.

This path needs no TDV 2200 escape-sequence knowledge - it is just "capture a byte stream from a serial line." It is the cleanest way to get real printing out of an emulator, and every mechanism it relies on is verified above.

Path B (faithful, but needs data you do not yet have) - aux printer port

Emulate Arrangement B: RetroTerm keeps acting as the TDV 2200 screen terminal, and additionally implements the terminal's auxiliary printer port:

  • Recognise the TDV 2200 control/escape sequences that turn the auxiliary ("transparent" / pass-through) printer mode on and off, and while it is on, route received characters to a printer sink instead of the screen.
  • Implement CTRL + PRINT as a local "dump current screen buffer to the printer sink" action.
  • Implement "Printer Mode = Log" as "copy all I/O to the printer sink."

UNVERIFIED / MISSING DATA: the exact TDV 2200 control sequences for auxiliary-print on/off are not in the manuals in this repository. The System Supervisor manual documents the setup and behaviour (handshake, code format, CTRL+PRINT, Printer Mode = Log) but not the byte-level escape codes RetroTerm would need to detect. To implement Path B faithfully you need one of:

  • a Tandberg TDV 2200 terminal / programmer's reference manual (the auxiliary-print / transparent-print escape sequence), or
  • a capture of a real ND-100 -> TDV 2200 session that uses CTRL+PRINT or an application "print" so you can see the sequence on the wire.

Until you have that, Path A is the reliable choice. (I can research the TDV 2200 control set if you want to pursue Path B - just say so.)

6. Summary

Question Answer
Is PRINTER a special device? No - it is a printer on an ordinary async terminal line (Arrangement A) or on a terminal's auxiliary printer port (Arrangement B). It reuses normal terminal hardware.
How is the line prepared? *SET-SPOOLING-DEVICE-NUMBER, disable background/login (*REMOVE-FROM-BACKGROUND-TABLE), set line speed with *CHANGE-DATAFIELD, create peripheral + spooling files.
Shared with a Tandberg? Tell SINTRAN via *CHANGE-DATAFIELD ... TINFO 20! / DFLAG 1000 and set the Tandberg printer menu (XON/XOFF or DTR, 7even, 9600). CTRL+PRINT dumps the screen; Printer Mode = Log logs the session.
Terminal type to declare @SET-TERMINAL-TYPE 54 (TDV2200-Standard) or the matching /9 variant.
RetroTerm - easy path Dedicate a line as PRINTER, capture the raw stream to a file/PDF (Path A). No escape-sequence knowledge needed.
RetroTerm - faithful path Implement the TDV 2200 auxiliary printer port + CTRL+PRINT + Printer-Mode-Log (Path B). Needs the TDV 2200 escape sequences, which are not in these manuals.