I've heard about dual-SIM phones before but only from not very well known Chinese manufacturers so my interest in them was not very high. Also, I assumed that while those phones could hold two SIMs, only one would be active at a time. While browsing the phones available at a mobile phone shop recently, I noticed that I've been wrong on both accounts.
Samsung has released two dual-SIM (GSM only) phones, the D880 at the end of 2007 and the D780 in the middle of this year, both capable of having both SIMs active simultaneously. Kudos for their courage, I am sure network operators are not very keen to see these phones.
For details see GSMArena:
Here are some technical details from the reviews above which hints how the dual-SIM functionality is implemented:
- A master SIM card has to be declared which can be used in 900/1800 and 1900 MHz. This SIM is also used for GPRS/EDGE.
- The secondary SIM card can be used for incoming and outgoing calls and SMS messages but only 900 and 1800 MHz.
To me this seems to indicate that each SIM card has its own GSM module and the second one is only dual band capable. Unfortunately, the review doesn't mention if an SMS can be received via the secondary SIM card while being in a voice call with the first SIM card. This would certainly prove it.
With the D880 available for around 200 euros and the D780 for even less, I can quite imagine that I will pick one up and give it a try myself. After all, it could reduce the number of phones I have to carry around with me these days by at least one. Not sure if they are a hit in sales statistics since I can't imagine network operators selling or even advertising them directly. In many countries, however, like in Italy and Germany for example, these phones can be bought from independent stores. If I were Samsung, I'd opt for a viral marketing strategy for those phones.