Someone on reddit acquired a Sabre-ADS terminal, Model 757. They were used for airline reservation and probably connected to an IBM mainframe.

Is there anything known about the pinout and workings of the interface connectors, so one can hook them up to other hardware like a PC, and replace the missing keyboard somehow?

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    Show a clear picture of the model and part nos. I suspect this is just a rebranded serial terminal, and the model number will give you well-known pinouts for those ports. Once you have that, this is easily a serial terminal for any number of systems.
    – user12
    Commented Apr 28, 2016 at 20:53
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    @jdv: It's not a "simple" serial terminal. I don't know if you've every seen someone working with such an airline reservation system (I have): it uses blocked mode, which means the operater can change "unprotected" data fields, and those get send to the mainframe in one go. Googling "sabre icot model 757" finds stuff for sale, but no manuals or pinouts. I don't own this thing, so I can't take pictures.
    – dirkt
    Commented Apr 29, 2016 at 6:07
  • Yes, this is similar to green screen terminals used on IBM mainframes. Which means there is probably a few lines that are just pure serial comms. You can also try to reverse engineer using that dongle. Unless you have this thing in your possession I don't see how it is of any value to you.
    – user12
    Commented Apr 29, 2016 at 12:43

2 Answers 2


The SABRE system was an airline reservation system that spun off from SAGE. This was an IBM system and I believe the airline reservation terminals used SNA and SDLC for the communication protocols. I have a bunch of airline terminals as well and at some point would like to connect them up to something. My thinking was to emulate SDLC using a microcontroller, or possibly other vintage IBM equipment.

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    Welcome to Retrocomputing. Could you provide some details about the protocols in your answer?
    – wizzwizz4
    Commented Nov 4, 2017 at 8:47
  • I provided as much as I know in the links.
    – legalize
    Commented Nov 6, 2017 at 22:18

If it's like the airline reservation terminals I'm familiar with, it will be using a 6-bit bisync serial multidrop protocol under the Airline Link Control (ALC) protocol umbrella. Searching for ALC, PARS, IPARS, TPF & SITA P1024B should give you all sorts of interesting info.

In theory, you could still hook it up to something. It's like an IBM 3270 terminal in that it's a block-mode terminal that requires a controller (called a PAD). You could find an ALC PAD; they're still made or you could find a used one from someone like CR Systems. As late as Cisco IOS 12.4, ALC PAD code was in the Cisco IBM feature set if you had the right physical interfaces in your router; I don't know about IOS 15 or later. Probably other routers could do that too. That gets the terminal talking on a network. But then, as far as I know, you really need a mainframe running TPF or the equivalent to get the terminal to do anything useful. Maybe TPF could run on the Hercules emulator; I've never heard of anyone trying that.

Talk to Linux? I dunno...maybe terminal->PAD->token ring/X.25/sync serial->Linux->tn3270. Just a guess, but I doubt it.

If all that doesn't put one off, the keyboard is undoubtedly completely proprietary. If you don't have it, it's unlikely to be documented anywhere well enough to adapt something else. That's probably a show stopper.

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