Was it 110, 135, then 300?

I'm not sure if there was _a_ progression, but anyway... No, the first two speeds were not pre-modem technology. The early Teletypes (with the five-bit character codes) work at around 45 bps (or more if you change the gears). The later models with ASCII work at 110 bps. Many units have direct connections through current loops, but some have modems. BTW, the technique they use is still used today and called by the same name: Frequency Shift Keying. "Frequency shift" is because the two bits are represented by tones of slightly different frequencies, "keying" because the Teletype was regarded as a distant descendant of Morse's telegraph key. There is an intermediate machine, named after its inventor Wheatstone, which uses a typewriter keyboard, punched paper tape, and electric transmission of the signal, but works directly in Morse Code! The printer that goes with this setup prints dots and dashes on a narrow strip of paper.) The 135-bps speed was created by IBM for their typewriter terminals. Another type of machine -- which uses a modem but for an analog signal -- is a certain type of fax machine. It's not necessarily relevant but it's interesting (and fun to watch). -- Derek