68kMLA Classic Interface

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QuickTime Video Conferencing ISDN DAV Kit
Posted by: jeremywork on 2022-06-03 15:02:23 I think my first post of this was lost so I'm re-adding the photos, plus I found a second loose card from Japan which is slightly different. This one's processor seems to have a removable daughtercard, but it seems to be stuck enough that I don't feel comfortable removing it.
Posted by: NJRoadfan on 2022-06-03 16:27:18 There is a reason for the difference. In the USA, ISDN modems came with the NT1 interface built-in and were expected to connect to the 2-wire "U" interface provided by the phone company off the street. The rest of the world's phone companies tended to view the NT1 interface as service provided equipment and installed one on-site to users, providing a 4-wire "S/T" interface to end-user equipment. There are also differences in the actual on-the-wire protocol. Europe had a unified "EuroISDN" signaling system, while the US had multiple depending on the type of central office you were connected to. The WE/Lucent 5ESS and Nortel DMS-100 were the most common standards.
Posted by: jeremywork on 2022-06-03 16:46:28 There is a reason for the difference. In the USA, ISDN modems came with the NT1 interface built-in and were expected to connect to the 2-wire "U" interface provided by the phone company off the street. The rest of the world's phone companies tended to view the NT1 interface as service provided equipment and installed one on-site to users, providing a 4-wire "S/T" interface to end-user equipment. There are also differences in the actual on-the-wire protocol. Europe had a unified "EuroISDN" signaling system, while the US had multiple depending on the type of central office you were connected to. The WE/Lucent 5ESS and Nortel DMS-100 were the most common standards. Thanks for reminding me of this. I think I last learned about it when I had a 550c on the bench and notice its "Express Modem DAA II" module. (compared to a US spec Global Village A540, which requires the secondary card installed under the RAM module)
Posted by: jeremywork on 2022-11-28 01:52:13 Looking more closely at these it seems they're manufactured by Groupe SAGEM/SAT, as their EasyTransfer Light software is included and the logo matches the one in the silkscreens. For completeness here are condensed photospreads, scanned documentation PDFs, imaged diskettes, and the ROM (M27C256B/PLCC32) from the ISDN cards; ROM contents are identical between the two pictured.
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