The Commodore AUTOMODEM (Model 1650)

The Commodore 1650, also known as the “AUTOMODEM”, is Commodore’s first full modem directly connected to the phone line. It supports pulse dialing in software and 300 baud duplex connections.

Historical Context

Year Name Model Description
1982 VICMODEM 1600 connected to phone’s handset connector; manual dialing through phone; Motorola MC14412
1982 AUTOMODEM 1650 connected to phone line, pulse dialing in software; Motorola MC14412
1985 MODEM/300 1660 added tone dialing support by feeding SID output into modem; Texas Instruments TMS99532A
1987 MODEM/1200 1670 Hayes command set; pulse and tone dialing in hardware; 300/1200 baud support; U.S. Robotics chipset


On the front, there is the VIC-20/C64 user port connector and an activity LED.

On the left, there is
* the “LINE” jack that is supposed to be connected to the telephone network
* the “PHONE” jack for connecting an existing telephone
* a D/T switch. In D mode, the modem takes over the phone line, in T mode, “LINE” gets passed through to the telephone.
* an A/O switch. When making a modem call, it is to be put into the “O” (originate) position, and when answering a call, it is to be put into the “A” (answer) position.

On the right, there is an H/F switch to select Half Duplex (“H“) or Full Duplex (“F“).

The label on the bottom says:

Commodore Business Machines, Inc
Made in USA

Certified to comply with the limits for a Class B
computing device pursuant to Subpart J of
Part 15 of FCC Rules. See instructions if
interference to radio reception is suspected.

Complies with Part 68, FCC Rules; FCC
Registration Number B4V8N2-70317-
DM-R; Ringer Equivalence 0.1B; Jack

Model 1650
Serial Number: 018208

The only text on the board is “00312A” on the back. The core component is the Motorola MC14412 modem chip at the bottom center.

The design of the AUTOMODEM is basically the same as its predecessor’s, with the extra circuitry added to allow it work with the phone line directly instead of acting as the handset of an existing telephone.



More Box Contents & Tape

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1 thought on “The Commodore AUTOMODEM (Model 1650)”

  1. I will always remember the 1660 modem! For years the computer store I worked at sold the 1650 modem and had lots of happy customers, I should know, I also ran one of the local BBSes.

    Then this person came in saying we sold him a piece of junk, the modem we sold did not work! I asked to see it and noticed it was the 1660 modem, not the 1650 most people had. He then loudly claimed he was a nuclear engineer at the local nuclear plant and knew what he was doing and the modem was a piece of junk.

    Since it was a new model to me I asked for the manual. He then loudly (yes, I mean loudly) said he had already read the manual and it was of not help.

    I insisted I needed the manual to configure it. And after having to even have my boss backing me up, he finally handed over the manual.


    There was no way he read the manual, and once I opened it to the section on switch settings, I got it configured and tested working in MINUTES.

    He left, and learnt, that even a nuclear engineer with an university education will lie about why their computer equipment does not work.

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