Car phones.

[Nick Harvey]

If, as Lorna says, it's a "GSM" phone, then it'll obviously work on both the 900MHz and 1,800MHz networks.

Otherwise it wouldn't conform to the GSM standard.

[cwathen]

If, as Lorna says, it's a "GSM" phone, then it'll obviously work on both the 900MHz and 1,800MHz networks.

Otherwise it wouldn't conform to the GSM standard.

Probably venturing in dangerous waters here Mr Harvey, but my understanding is that GSM usually operates on 900/1800Mhz in Europe, 850/1900Mhz in USA/Canada, and on 400/450Mhz in a small number of countries which re-used old analogue mobile frequencies rather than allocate new ones for digital.

I've never been aware of it being necessary for a handset to support operation on more than one band to be able to call itself a GSM handset - indeed there was a gap of several years between the first 900Mhz and first 1800Mhz networks.

Also, the box to my first mobile specifically has 'GSM1800' on the outside of it, and if you perform a manual network scan it will find Orange and T-Mobile, but not Vodafone or O2.

[Nick Harvey]

Also, the box to my first mobile specifically has 'GSM1800' on the outside of it, and if you perform a manual network scan it will find Orange and T-Mobile, but not Vodafone or O2.

Exactly.

If it is designated GSM900 it works in the 900MHz band.

If it's designated GSM1800 it works in the 1,800MHz band.

If it's designated just GSM and was sold in the United Kingdom, it has to work on both the 900MHz AND the 1,800MHz bands.

That's what I just said above.