© Mark Ollig
AT&T introduced the Bell 103 dataset modem in 1962.
The Bell 103 operated at 300 baud with full-duplex data transmission speeds up to 300 bits per second (bps) over standard analog telephone lines.
The Bell 212A, a 1,200-baud analog modem that could transmit data at 1,200 bps, was introduced by AT&T in 1976.
These early modems transmitted one bit per baud, so a 300-baud modem would transmit at 300 bps and a 1,200 baud at 1,200 bps.
A modem (modulator/demodulator) is a peripheral hardware device that converts digital signals to analog for transmission over a standard telephone line and then back to digital at the receiving end.
Baud rate measures the number of times a signal changes state per second in determining the data/signal transmission rate. A signal can be a voltage, frequency, or waveform phase change.
The term “baud” originated from Jean-Maurice-Émile Baudot, a French telegraph engineer who invented the Baudot code in 1870.
The Baudot code is a five-bit binary character code used in the telegraph system. A five-bit combination of current-on or current-off signals of equal duration represents each alphabet letter.
The code represented a major improvement from the earlier Morse code, which relies on dots and dashes.
The Baudot code paved the way for digital coding systems in today’s communication channels.
The baud rate can differ from the bit rate, which is the number of bits transmitted per second.
If a modem packs multiple bits into each signal change, the bit rate can be higher than the baud rate.
For example, a modem packing eight bits into each baud can transmit at a bit rate of 9,600 bps, even though the baud rate is only 1,200 baud because 9,600 bps equals 1,200 baud multiplied by eight bits per baud.
But I digress.
In 1977, Dale Heatherington and Dennis Hayes designed and assembled the first 1,200-baud modem circuit board for personal computers.
The two formed DC Hayes Associates, renamed Hayes Microcomputer Products in 1980.
Computer users began installing Hayes modems to access dial-up computing services.
On Oct. 16, 1983, the Davenport Iowa Quad-City Times newspaper advertised a Hayes 1,200 Baud Modem for $595.
The hobbyist dial-up computer Bulletin Board System (BBS) I operated, “WBBS OnLine!,” could be accessed through four telephone lines connected to Hayes modems.
During the 1980s, computer users with a 1,200 baud modem logged onto dial-up commercial BBS platforms like CompuServe, Prodigy, GEnie, AOL, and BIX.
There used to be tens of thousands of non-profit hobbyist dial-up BBS platforms nationwide, accessible using 1-800 and local telephone numbers, like WBBS OnLine!
In the early 1980s, I used a Panasonic KX-D4920 portable data terminal with a built-in modem while working at the Winsted Telephone Company.
The words “1,200 BAUD HIGH SPEED” were written in bold blue font on the face of the data terminal.
As far as I was concerned, a 1,200-baud modem was state-of-the-art.
I used the KX-D4920 connected to modems over dedicated phone lines to program data for the Winsted Telephone Company Nortel DMS-10 digital telephone switching platform and other companies’ private branch exchange digital telephone systems.
The 1,200 baud data terminal operated in an asynchronous, full-duplex mode, whereby data can be transmitted and received in both directions simultaneously over a communications channel.
The KX-D4920 data terminal included a full QWERTY keyboard and acoustic couplers, which were “muffs” that held in place a telephone handset. The handset was connected to the data terminal to send and receive audible computer data through the standard analog telephone line.
The two-line LCD screen displays 80 characters of typed data and allows editing before pressing the enter key and sending my program data to the digital switching platform I was logged into.
The KX-D4920 could also communicate with business or home computers via modem access.
A popular data terminal, the KX-D4920, was widely used by computer and telephone technicians alike.
Although 1,200 baud modems are now obsolete, they were a technological advancement and a stepping stone to today’s broadband “high-speed” data transmission rates.
After 40 years, the 17-pound KX-D4920 model terminal I once regularly used has become another part of telecom history.
Since we are taking a trip down memory lane, I got the old data terminal out of mothballs, cleaned it up, put a fresh roll of thermal paper in the holder, plugged it into an AC outlet, and turned the power on.
All the lights on the data terminal lit up. I typed a sentence on the keyboard that appeared on the LCD screen.
Taking a breath, I pressed the enter key.
The familiar sound was heard of the paper roller bar moving and the nine-dot printhead motor whirring as it applied pressure and heat to the surface of the thermal paper, displaying the words I typed.
The KX-D4920 internal 1,200 baud modem would have probably worked, but no operating platforms are available to test it.
I uploaded this brief video at: https://tinyurl.com/BBD4920.
Jean-Maurice-Émile Baudot died March 28, 1903, at 57, in Sceaux, France.
