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Going out on a limb here, but Didn't the original GSM phones work in a similar way, with no SIM and some sort of mapping to a phone number at the carrier end
by CaptainZapp 15y ago
Going out on a limb here, but
Didn't the original GSM phones work in a similar way, with no SIM and some sort of mapping to a phone number at the carrier end?
As far as I know (and recall), SIM was always part of the GSM specifications.
The first SIMs where credit card sized. Later generations where still credit card sized, but with a perforated breakout for the SIM as we know it (mostly).
The predecessor system (analogue mobile) didn't use SIM.
- kamjam 15y agoAhhh, it was the old analogue phones I was thinking of. I never had one, my brother did though. I remember the big sim card and the perforated ones too :)
- dfox 15y agoAnd while NMT phones didn't use easily (and user) replaceable SIM, they were paired to operator/number not by some database but by contents of replaceable EPROM chip in them. SIM cards were introduced not to make changing carriers possible, but easier and also more secure (NMT phones could be cloned without direct access to phone, only by eavesdropping on signaling channel).