I found your post - I hope that this will help a little bit.
Telex 1220 was among the first efforts by Telex to move into the IBM PC Market. Telex had several that they manufactured 1120/1180, 1220, & 1280. The 1180 had an 80186 Processor, The 1220 may have had a 286 Processor and the 1280 was a 386. Memory was via individual Memory IC Chips on board for a total of 64Kb to 1Mb. You could at the time get an add-on Memory PCB to add more memory, but not practical at the time cause everything was written to use the 64-128Kb Memory scheme. Networking was via a PCB from either IRMA, or some IBM 3270 compatible PCB. The Maximum HD at the time was 40Mb, but most came with 20Mb. Usually they had a 360Kb 5.25" FDD and a 720Kb/1.44Mb 3.25" FDD. Video was VGA, with some SVGA. If I remember correctly the Keyboard either used a DIN Plug or an RJ45. You could use the RJ45 also for a Light Pen.
Telex had a lot of things going for them with a lot of innovations planned. Telex at one time was very healthy and well respected in the 3270 market place as well as in the Mainframe Peripherial markets. They bought Raytheon Data Systems, and integrated their products into the Telex Family. About the time this came out, McMurdock was making noise about making a hostile takeover of Telex, so they began actively trying to court other computer manufactures to buy them - even went so far as to kick in a ton of money to Memorex (from Germany) which eventually completed the transactions.
I was laid off from MTC (Memorex-Telex Computer Products) in July of 1991 after a 10-yr stint. I started working on their Mainframe Peripherial (6420/8020 Tape Drives, Disk Drives, Printers and General Computer Systems) moved on to their REACT Product Lines (3270 without a Monitor) and the 3270 Products (IBM Compatible" Dumb/Mainframe Termials) and eventually Western Region Support for the PC Product lines. Wild times.
Hope you found something to use in this short history lesson - Might just consider donating it to some Tech School as a Museum piece or something.