[dspillett]

Very early on, mobile data was essentially an emulation of an analogue modem call, at blazing fast rates like 19200baud or less, held over the same channels as voice calls with a bit of extra jiggery-pokery, and were charged by the minutes just like voice calls. Sometimes they were charged as normal voice calls, sometimes you ended up being charged extra (or not being charged extra as such, but with data calls not being counted in any pre-paid minute allowance your plan had). It was vitally important to check this before making modem calls, as some providers charged data calls in the same band as premium rate voice calls, meaning that just picking up a few text emails could be quite expensive.

[cue misty eyed memories of trying to get my Psion 5mx to connect to the Internet by infra-red serial link to my phone, to try get updated connection information for my next train as the one I was on was going to be too late to make the planned connection…]