IBM System7use of Teletype as console 2545
IBM System7use of Teletype as console 2546
IBM did make PBXs - PABXs actually - but they were never sold in the US. I believe the 2750 was the only one that was even moderately successful, but there was also a later 3750...
PBX I first
Jay, I guess it was a PABX. I have no idea what model it ws but I guess it was a 2750 or a 3750. It sat in a room on the first floor of Jackson House, Washway Road, Sale, Manchester, England. I think there were two rows of racks, say 3 or 4 cabinets per rack with a golf ball console, I think it was a 2741, which sat in the corner. Oddly I can't find any announcement letters for theses PABXs, but there is announcement letter ZG82-0278 which describes a series-1 attachement and there are some articles in old IBM research journals. Take a look at:-
for example. I remember when I first strarted working in the local IBM office on Network-VM almost all the office kit was of IBM manufacture. As well as the usual typwriters, and the phone system as above, the copiers were all IBM made, and all with a serial etched in the glbutt so they could tell wich copied a documnet was copied on!. Oh and the door lock system ran on a netywork of Series-1s running EDX. But there again they were International Business Machines