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Bell Datasets - Completely clueless


Veteran Member
Oct 22, 2008
Kamloops, BC, Canada
I got badly bid under the table by some schmo of a telephone collector on ebay last week and I'm still annoyed. Anyways, I was going after what I can only assume was either a 101 or 103 dataphone which would of been right at home with my teletype machine and saved me weeks worth of time building a custom Hayes interface. After the dust began to settle I started looking elsewhere to see what else I could pick from. I've come across another organization that has what looks to also be rebadged Dataphones but finding solid information on any of it is being extremely hard. Bitsavers and the Internet Archive occasionally mention it or show a photo but never do into any level of detail on what it is.

Exhibit A:

Calls itself the 804A(6). Uses that 50 pin telco interconnect and is shallower than a regular dataset. That might be because it's not actually a modem. It's possibly just the controls and handset for the modem. Completely useless for what I want? (my teletype already has a remote control in the CCU pocket) I don't know.

Exhibit B:

Calls itself the GDC-402C which I can only assume translates to the 402C dataset. Same 50 pin telco connector (with the opposite gender suspiciously) but it at least clearly states it is a modem. Compatible with the 804? No idea. Only paperwork I could find indicates it is rated for up to 75 characters per second and is transmit only. Doesn't list a baud rate. The interface is supposedly a "Binary Parallel Interface" which sounds pretty distant from just saying "RS-232C"

Any of the old salts better off explaining any of this before I end up burning myself on equipment I don't need?
Last edited:


25k Member
Jan 11, 2007
Pacific Northwest, USA
The 402C is a transmit-only; the 402D is the receive only. I don't know what that thing is; at first, I was thinking 212A, but I wonder if it's really a WE product. Looks an awful lot like a 212A.