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I've always wondered: can a single phone have radios for all the different carriers? Could they share a single antenna? Could one be activated by the user selec

I've always wondered: can a single phone have radios for all the different carriers? Could they share a single antenna? Could one be activated by the user selecting which network to get on?

jarek 13y ago
I don't know about CDMA vs GSM, though I think it might work (there definitely are two-GSM-SIM phones, and GSM-and-CDMA doesn't seem philosophically different). Having a phone work on both AT&T and T-Mo, though, is easy, Galaxy Nexus or Nexus 4 can do that, just to name a couple of popular ones.
kalleboo 13y ago
> can a single phone have radios for all the different carriers? All carriers in a single country? Yes, many do. All carriers worldwide? You'd be putting a lot of radios in the thing. > Could they share a single antenna? Not a radio expert, but I think each antenna has to be tailored to each wavelength. Maybe you can get away with one per band (one for 800-900, one for 1800-1900, one for 2100-2600) > Could one be activated by the user selecting which network to get on? You'd need a SIM card for each carrier you want and swap them out, and for American CDMA carriers you'd have to have your ESN registered with their networks beforehand.
- PeterisP 13y ago
  > You'd need a SIM card for each carrier you want and swap them out There are phone models that support 2-3 SIM's , very useful when travelling so you don't have to swap anything but can call from different networks seamlessly.
- vidarh 13y ago
  All carriers worldwide would be tough, but a sufficiently multi-band GSM phone will typically give you pretty much worldwide roaming from a variety of carriers. I'm in Europe. The last time I had a phone I couldn't effortlessly take to the US or Asia and use roaming was probably about '99.
  - kalleboo 13y ago
    Yeah, most modern phones will work most everywhere, but there'll always be one carrier's 3G or 4G network you'll miss out out. Some phones have really impressive radios in them now. Here's the Sony Xperia Z Ultra: 2G Network: GSM 850 / 900 / 1800 / 1900 3G Network: HSDPA 850 / 900 / 1700 / 1900 / 2100 4G Network (C6833 model): LTE 800 / 850 / 900 / 1700 / 1800 / 1900 / 2100 / 2600 4G Network (C6806 model): LTE 700 / 850 / 900 / 1700 / 1900 / 2100 / 2600 With one of these babies, pretty much all you're missing out on is extended range areas on Docomo Japan (800 MHz)
jlgreco 13y ago
If the wireless situation doesn't resolve itself in the next few years, I suspect that it will drive software defined radio deployment to the masses. One phone with one antenna and chunk of silicon that can speak on any network, software permitting.
vidarh 13y ago
"All" I don't know about, but got to Aliexpress.com and search for "GSM CDMA" - you'll get a bunch of phones supporting multiple standards. Many Chinese phones even sell with from two and up to 4 GSM SIM slots (that can be active simultaneously), so I wouldn't be surprised if you could even use both at the same time.

I've always wondered: can a single phone have radios for all the different carriers? Could they share a single antenna? Could one be activated by the user selecting which network to get on?

jarek 13y ago

I don't know about CDMA vs GSM, though I think it might work (there definitely are two-GSM-SIM phones, and GSM-and-CDMA doesn't seem philosophically different). Having a phone work on both AT&T and T-Mo, though, is easy, Galaxy Nexus or Nexus 4 can do that, just to name a couple of popular ones.

kalleboo 13y ago

> can a single phone have radios for all the different carriers? All carriers in a single country? Yes, many do. All carriers worldwide? You'd be putting a lot of radios in the thing. > Could they share a single antenna? Not a radio expert, but I think each antenna has to be tailored to each wavelength. Maybe you can get away with one per band (one for 800-900, one for 1800-1900, one for 2100-2600) > Could one be activated by the user selecting which network to get on? You'd need a SIM card for each carrier you want and swap them out, and for American CDMA carriers you'd have to have your ESN registered with their networks beforehand.

PeterisP 13y ago
> You'd need a SIM card for each carrier you want and swap them out There are phone models that support 2-3 SIM's , very useful when travelling so you don't have to swap anything but can call from different networks seamlessly.
vidarh 13y ago
All carriers worldwide would be tough, but a sufficiently multi-band GSM phone will typically give you pretty much worldwide roaming from a variety of carriers. I'm in Europe. The last time I had a phone I couldn't effortlessly take to the US or Asia and use roaming was probably about '99.
- kalleboo 13y ago
  Yeah, most modern phones will work most everywhere, but there'll always be one carrier's 3G or 4G network you'll miss out out. Some phones have really impressive radios in them now. Here's the Sony Xperia Z Ultra: 2G Network: GSM 850 / 900 / 1800 / 1900 3G Network: HSDPA 850 / 900 / 1700 / 1900 / 2100 4G Network (C6833 model): LTE 800 / 850 / 900 / 1700 / 1800 / 1900 / 2100 / 2600 4G Network (C6806 model): LTE 700 / 850 / 900 / 1700 / 1900 / 2100 / 2600 With one of these babies, pretty much all you're missing out on is extended range areas on Docomo Japan (800 MHz)

jlgreco 13y ago

If the wireless situation doesn't resolve itself in the next few years, I suspect that it will drive software defined radio deployment to the masses. One phone with one antenna and chunk of silicon that can speak on any network, software permitting.

vidarh 13y ago

"All" I don't know about, but got to Aliexpress.com and search for "GSM CDMA" - you'll get a bunch of phones supporting multiple standards. Many Chinese phones even sell with from two and up to 4 GSM SIM slots (that can be active simultaneously), so I wouldn't be surprised if you could even use both at the same time.