Well, look at the specs of the Milestone:
Voice Bands:
GSM 850/900/1800/1900
W-CDMA 900/2100 or 850/1900/2100
Data Bands:
GPRS/EDGE Class 12
HSDPA 10.1
HSUPA 5.7
---
The iPhone specs are the following:
So, given it supports HSDPA and EDGE, at the same Frequencies as the iPhone, (And this is taking the specs off the US website), it should be, technically, compatible with the AT&T network, so long as he takes the SIM from his AT&T GSM phone and stick it in his Milestone.
His only real drawback will be the inability to use some of the AT&T services that AT&T supports via phones, given it is not a supported phone, and he will not get any OTA updates, as it is usually the carrier that pushes out the updates for the phones versus the manufacturers like Motorola. Otherwise, I am sure a lot of us Droid users would be hammering ther crap out of Motorola for the early Droid OS update only 1000 users have gotten so far.
Voice Bands:
GSM 850/900/1800/1900
W-CDMA 900/2100 or 850/1900/2100
Data Bands:
GPRS/EDGE Class 12
HSDPA 10.1
HSUPA 5.7
---
The iPhone specs are the following:
- UMTS/HSDPA (850, 1900, 2100 MHz)
- GSM/EDGE (850, 900, 1800, 1900 MHz)
So, given it supports HSDPA and EDGE, at the same Frequencies as the iPhone, (And this is taking the specs off the US website), it should be, technically, compatible with the AT&T network, so long as he takes the SIM from his AT&T GSM phone and stick it in his Milestone.
His only real drawback will be the inability to use some of the AT&T services that AT&T supports via phones, given it is not a supported phone, and he will not get any OTA updates, as it is usually the carrier that pushes out the updates for the phones versus the manufacturers like Motorola. Otherwise, I am sure a lot of us Droid users would be hammering ther crap out of Motorola for the early Droid OS update only 1000 users have gotten so far.