Qualcomm Inc (QCOM)

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GSM 1X switches easily from GSM to CDMA
Zatni Arbi, Contributor, [e-mail]

http://www.thejakartapost.com/detailfeatures.asp?fileid=20050425.S01

As we all expected many years ago, today we have both GSM and CDMA cellular phone operators. To use a GSM cellular phone, we need a SIM (Subscriber Identity Module) card. If we change cellular phones, all we have to do is take it out from the old one and insert it into the SIM slot in the other cellular phone device. The SIM card is actually a chip card that contains our cellular phone number, all the contact info that we have saved on it and some other information.

To use a CDMA cellular phone, we may also need a RUIM (Removable User Identity Module) card. CDMA operators such as Esia and Telkom Flexi will provide the RUIM card that we have to insert into the RUIM slot in our CDMA cellular phone.

In the past, we could also ask them to "inject" the phone number into the device itself, so no RUIM would be necessary. I have a CDMA phone that was given to me by Japan's KDDI during a trip there two years ago. As it does not support RUIM, the pretty cellular phone is now just a part of my collection.

Now, with our pockets already so full of electronic gadgets, we wonder if there is any way we can use both SIM and RUIM in one single cellular phone. Keep in mind that, technically, the access method of GSM is different from that which CDMA uses. Besides, they use different frequency bands, too. Thus, designing a cellular phone that can access a GSM and a CDMA network at the same time would appear to be out of the question.

Dual-Mode Cellular phone

Qualcomm, the San Diego-based company that has been developing CDMA technology, has the solution. This company, which has also been making chips for CDMA devices, has developed what it calls the GSM 1x chip.

On the device side, the technology provides a solution that will allow engineers to design dual-mode handsets that can connect to either a CDMA or a GSM network with the help of an electronic switch. On the infrastructure side, the GSM 1x technology allows GSM operators to add advanced CDMA2000 capabilities on top of their network.

It means that subscribers can get a higher data capacity -- up to 2.4 Mbps -- over their GSM network and enjoy the CDMA2000 1x-EVDO services.

Of course, this is a controversial solution, especially with the 3G WCDMA, which is a pure GSM breed, gaining ground rapidly. Certainly, operators will have a difficult decision to make, namely, whether to go with 3G WCDMA or to implement GSM 1x.

Keep in mind, too, that the data capacity of a 3G WCDMA -- not the HSDPA -- is only 384 Kbps, far below the CDMA2000 1x. However, now that the HSDPA Phase 2 is reportedly providing a data rate of up to 14 Mbps, the GSM 1x may not seem so attractive any more.

Nonetheless, at least now with a minimal fuse you can switch a cell phone from GSM to CDMA if it has a GSM 1x chip. So, if you are traveling to South Korea or Japan, you no longer have to carry two cellular phones in your bag. Switch to CDMA when you are there, and switch back to GSM after you have returned.

Courtesy of Motorola, I was able to play around with their GSM 1x cell phone for a week. The A860 has two slots, a RUIM card slot and a SIM card slot. The latter is located inside the battery cover. We do not have to fill both slots to use the cellphone.

One thing to keep in mind is that, contrary to what most people think, you cannot use both the CDMA and the GSM service at the same time, you will have to switch to either of them.

There are a lot of things to like about the A860. Firstly, I had no complaint about the keypad, which was very easy to use and accurate. The overall clamshell design can be called a classic, and the screen is just great. Considering that it is actually two cellular phones in one, it was surprising small in my hand.

The audio is great, too. About the only complaint I have was that the battery life seemed to be a bit on the short side. I was able to use it only for 24 hours, and I sent and received only a dozen SMSes. However, this may have to do with the fact that the demo unit I was test driving had been used by several other journalists before, and they might not have recharged the battery properly.

Although it is a nice cellphone to have, the Motorola A860 was actually made for China Unicom. If you press a particular button, a message on the screen will read "This service is available only on China Unicom." Still, the A860 does represent a solution for those who have constantly have to switch between a CDMA and a GSM network -- or even between two GSM networks.