VICMODEM [Model 1600]
The Commodore 1600, also known as the “VICMODEM”, is Commodore’s very first modem (1982): It supports 300 baud duplex connections, and is connected to an existing telephone’s handset connector instead of the phone line. This kept the price down, but required the user to dial manually through the phone.
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 back, there is the RJ11C handset connector. On the side, there is an LED indicating that indicates when the phone is transmitting or receiving, and a switch that can be put into the “A” (answer) or “O” (originate) position, depending whether a phone call is supposed to be made or accepted.
On the front, there is the VIC-20/C64 user port connector.
The RJ11 connector on the back must be connected to an existing phone, instead of its handset.
The VICMODEM does not talk on the phone line level, but on the handset level, this reusing the hardware in the existing phone. This allowed the modem to be produced for under $33, so it could be the first modem to be sold for under $100.
The flip side of this design was that the modem could not dial or answer by itself. To dial a number, it had to be keyed into the telephone with the handset connected, and once one would hear that the remote side picked up, switch the cable to the modem. To wait for a call and answer it, the modem has to be connected and the (unconnected) handset has to be in the cradle. Once it rings, the handset has to be picked up and set aside.
This is exactly how one would operate an acoustic coupler. After all, this modem is more of an acoustic coupler with a direct audio connection than a full modem.
In late 1983, the modem was already sold for under $70.
Software download
VICMODEM manual
additional material
