Using Two Phones With A Single Number

[wynzlo]

A few months ago I either lost my iPhone or it got snatched -- not sure exactly what happened. It was an unlocked AT&T version from the US and worked nicely with TRUE prepaid (voice/sms only). Considering how much a new one is here, I just went with a cheapo Nokia. Went to one of the TRUE stores in Chiang Mai and they had a new SIM ready for me in minutes -- same number, and even had my remaining credit on it.

I might be making a trip to the US soon and am thinking about getting a new iPhone. I was thinking it would be real nice to have two phones, the iPhone and then the beater Nokia, both using a single number. Unfortunately swapping the SIM out of an iPhone isn't just a matter of popping a cover off, otherwise I'd be happy moving a single SIM between phones.

Does anyone know if two phones can work with the same number? TRUE didn't seem to think twice about giving me a new copy of the SIM card, I imagine it's routine for them. Any complications?

[jackbox]

When they gave you the new SIM your old SIM was deactivated. Each sim has a unique number (something like 15 or 18 digits). When your phone registers to the system the phone transmits its IMEI and the SIM serial number. These must match or the registration to the network will fail. So you cannot just go get another SIM and use both of them. Also if you did clone a SIM and the same number was active on the network on two phones at the same time the number would be deactivated as this is a violation of the terms of service.

On the other hand, the carriers offer a service they call multi-sim where they will give you two sims on the same number but only one can be active for receiving and making calls at any given time. The other sim will still register to the network but for data services only. For your situation this would be ideal. Whatever phone you want to call on or receive calls on you enter a code on the phone and hit send to activate the sim for calls. When you switch phones you do it again to switch the sim that can make and receive calls. Some carriers require a postpaid account for this service and others will do it on prepaid. Not sure what TrueMove's deal is. Call them or go into a True store and ask them about multi-sim service.

[wynzlo]

When they gave you the new SIM your old SIM was deactivated. Each sim has a unique number (something like 15 or 18 digits). When your phone registers to the system the phone transmits its IMEI and the SIM serial number. These must match or the registration to the network will fail. So you cannot just go get another SIM and use both of them. Also if you did clone a SIM and the same number was active on the network on two phones at the same time the number would be deactivated as this is a violation of the terms of service.

On the other hand, the carriers offer a service they call multi-sim where they will give you two sims on the same number but only one can be active for receiving and making calls at any given time. The other sim will still register to the network but for data services only. For your situation this would be ideal. Whatever phone you want to call on or receive calls on you enter a code on the phone and hit send to activate the sim for calls. When you switch phones you do it again to switch the sim that can make and receive calls. Some carriers require a postpaid account for this service and others will do it on prepaid. Not sure what TrueMove's deal is. Call them or go into a True store and ask them about multi-sim service.

jackbox,

Thanks so much for explaining that so clearly. I was hoping there would be some knowledgeable folks such as yourself here

One question:

You mention "The other sim will still register to the network but for data services only". Does this mean SMS messages could be delivered to both phones?

[astral]

When they gave you the new SIM your old SIM was deactivated. Each sim has a unique number (something like 15 or 18 digits). When your phone registers to the system the phone transmits its IMEI and the SIM serial number. These must match or the registration to the network will fail.

This is not totally correct.

The IMEI was checked back in the early days of mobile phones in Thailand to make sure

you only used phones bought from the network supplier.

Orange broke this monopoly.

Today only the SIM is checked, but that must match the record with the network provider.

You can try asking if they will provide a second SIM for the same number.