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And then there’s dual SIM (or even quad SIM). It’s a feature that’s really popular in Asia and Latin America where people might use one network for a loca

And then there’s dual SIM (or even quad SIM). It’s a feature that’s really popular in Asia and Latin America where people might use one network for a local call and another for an international one. That’s largely something MediaTek drove, but now it’s in the Moto E, which also has a feature called SmartCalling to help people set up and swap between SIM preferences and automatically configure access point names. https://bbot.org/blog/archives/2013/10/28/programmatically_advertising_mobile_bandwidth_cost_a_proposal/ https://bbot.org/blog/archives/2013/10/28/programmatically_a... You know what would be cool? If your phone knew how much bandwidth from each carrier cost, and could switch between them on the fly, depending on which one was cheapest, like a multi-SIM phone that didn't suck.

xur17 13y ago
Out of curiosity - How does dual SIM work? Does the phone register with both networks, or does it switch allow you to quickly switch over before making an outgoing call?
- noselasd 13y ago
  You're registered to one of them at a time. Baseband chips typically only handle 1 network at a time. Here's an example http://www.youtube.com/watch?v=nw76tsRKa_Q#t=44 http://www.youtube.com/watch?v=nw76tsRKa_Q#t=44
  - userbinator 12y ago
    It depends on the type of dual SIM exactly; it could mean anything from not more than being able to switch between two SIMs, to being able to use both of them simultaneously. The Mediatek dual SIM phones do register to both networks at a time, they have two IMEIs as well. http://www.youtube.com/watch?v=Ro7k4itFT-U http://www.youtube.com/watch?v=Ro7k4itFT-U
- Ecio78 12y ago
  afaik there are two different ways of operating: DSDS (Dual Sim Dual Standby) e DSFA (Dual Sim Full Active). The most common is the first one, where the phones are both registered but when you're communicating with one sim the second one is unreachable (as there's only one radio circuit, one antenna, one processor etc..). The second one, as the name says, allow you to use them both but it's more expensive of course because of the presence of two circuits of everything (at least radio-wise, it's like having two different phones in one) so it's far less common. As far as I know almost all the "chinese" dualsim phones fall in the first category.
justincormack 13y ago
You get the usage split out by SIM in the usage screen, so implementing this should not be hard.
lucaspiller 13y ago
I'm not sure how well this would work in reality, for starters most dual SIM phones only provide 3G service onone of the SIMs, you have to physically swap then over if you want it on the other. Such an app would also need to keep track of the credit on each SIM, bearing in mind there is no standard way to do so among all operators. It would also need to deal with differences between the phones reported data usage and the operators measured.
relix 13y ago
There's a service that does something like this: http://www.knowroaming.com/ http://www.knowroaming.com/ It basically acts like a local SIM while you're roaming, including getting a local phone number.
netcan 13y ago
Dual SIM is such a cool feature and so common in asia that not having it in Western markets almost seems like a conspiracy. Work/private phone. Burner. Try out a new network. Add a local SIM when traveling.
- rokhayakebe 13y ago
  Technically you could get the functionality of dual sim with software, so ultimately this will be an app on every phone.
- pedrocr 13y ago
  >Dual SIM is such a cool feature and so common in asia that not having it in Western markets almost seems like a conspiracy. When the phone market is dominated by the carriers they don't supply dual-sim phones because they don't want people to easily switch or complement their networks. I know of at least one carrier-named phone sourced from ZTE, whose only difference from the original ZTE model is the removal of the second SIM slot.
  - maxerickson 13y ago
    Some of it is also the CDMA legacy of the U.S. (I guess the carriers probably liked that the system didn't use SIMs, but on the other hand, the technology has proven itself)
- plam 13y ago
  You can buy all sorts of Chinese phones (with dual SIM) directly from China online on sites like Aliexpress.com. The thing is, US uses weird 3G frequencies or something from the rest of the world. I bought my 3G MTK phone a year ago on Aliexpress.com. It worked fine perfectly while I was living in Europe. Then I came over and now I'm always on Edge network and network speed is significantly slower.
- icebraining 13y ago
  Not having it on Western markets? Are you sure you're not confusing US with Western? Here in our very western European country they're common and often advertised. Both my previous phone (crappy Samsung) as well as my current cheap Android were dual sim.
galuggus 13y ago
dual sim is popular in China Most android/feature phones will automatically choose which sim card to make a call with depending on what network you are on.

xur17 13y ago

Out of curiosity - How does dual SIM work? Does the phone register with both networks, or does it switch allow you to quickly switch over before making an outgoing call?

noselasd 13y ago
You're registered to one of them at a time. Baseband chips typically only handle 1 network at a time. Here's an example http://www.youtube.com/watch?v=nw76tsRKa_Q#t=44 http://www.youtube.com/watch?v=nw76tsRKa_Q#t=44
- userbinator 12y ago
  It depends on the type of dual SIM exactly; it could mean anything from not more than being able to switch between two SIMs, to being able to use both of them simultaneously. The Mediatek dual SIM phones do register to both networks at a time, they have two IMEIs as well. http://www.youtube.com/watch?v=Ro7k4itFT-U http://www.youtube.com/watch?v=Ro7k4itFT-U
Ecio78 12y ago
afaik there are two different ways of operating: DSDS (Dual Sim Dual Standby) e DSFA (Dual Sim Full Active). The most common is the first one, where the phones are both registered but when you're communicating with one sim the second one is unreachable (as there's only one radio circuit, one antenna, one processor etc..). The second one, as the name says, allow you to use them both but it's more expensive of course because of the presence of two circuits of everything (at least radio-wise, it's like having two different phones in one) so it's far less common. As far as I know almost all the "chinese" dualsim phones fall in the first category.

justincormack 13y ago

You get the usage split out by SIM in the usage screen, so implementing this should not be hard.

lucaspiller 13y ago

I'm not sure how well this would work in reality, for starters most dual SIM phones only provide 3G service onone of the SIMs, you have to physically swap then over if you want it on the other. Such an app would also need to keep track of the credit on each SIM, bearing in mind there is no standard way to do so among all operators. It would also need to deal with differences between the phones reported data usage and the operators measured.

relix 13y ago

There's a service that does something like this: http://www.knowroaming.com/ http://www.knowroaming.com/ It basically acts like a local SIM while you're roaming, including getting a local phone number.

netcan 13y ago

Dual SIM is such a cool feature and so common in asia that not having it in Western markets almost seems like a conspiracy. Work/private phone. Burner. Try out a new network. Add a local SIM when traveling.

rokhayakebe 13y ago
Technically you could get the functionality of dual sim with software, so ultimately this will be an app on every phone.
pedrocr 13y ago
>Dual SIM is such a cool feature and so common in asia that not having it in Western markets almost seems like a conspiracy. When the phone market is dominated by the carriers they don't supply dual-sim phones because they don't want people to easily switch or complement their networks. I know of at least one carrier-named phone sourced from ZTE, whose only difference from the original ZTE model is the removal of the second SIM slot.
- maxerickson 13y ago
  Some of it is also the CDMA legacy of the U.S. (I guess the carriers probably liked that the system didn't use SIMs, but on the other hand, the technology has proven itself)
plam 13y ago
You can buy all sorts of Chinese phones (with dual SIM) directly from China online on sites like Aliexpress.com. The thing is, US uses weird 3G frequencies or something from the rest of the world. I bought my 3G MTK phone a year ago on Aliexpress.com. It worked fine perfectly while I was living in Europe. Then I came over and now I'm always on Edge network and network speed is significantly slower.
icebraining 13y ago
Not having it on Western markets? Are you sure you're not confusing US with Western? Here in our very western European country they're common and often advertised. Both my previous phone (crappy Samsung) as well as my current cheap Android were dual sim.

galuggus 13y ago

dual sim is popular in China Most android/feature phones will automatically choose which sim card to make a call with depending on what network you are on.