A cable modem isn’t

Nor is a DSL modem either but since I have a “cable modem” I’ll focus my annoyance there. I don’t know why this popped into my head today but it suddenly dawned on me that a “cable modem” isn’t a modem. Here’s a partial definition of ‘modem’ from HyperDictionary.com:

(Modulator/demodulator) An electronic device for converting between serial data (typically EIA-232) from a computer and an audio signal suitable for transmission over a telephone line connected to another modem. In one scheme the audio signal is composed of silence (no data) or one of two frequencies representing zero and one.

They key here is that a modem changes electronic pulses (didital signals) into audio signals (noise) so information can be transmitted over a phone line. At the other end it turns the noise back into a digital signal. Well, in the case of a “cable modem” there is a conversion of your singals to whatever is being transmitted over the cable itself, but it’s not an audio signal. There is no modulating going on, there is no conversion between digital and audio signals. Therefore it is not a modem. I’m sure we call them that purely out of sheer convienence but it’s still not correct. This would be like calling the card that connects me to a LAN a “LAN modem.”