Can I use a 3G modem to make a voice call

June 18, 2010 1:40 AM

Can you use a 3G modem+PC+soundcard+speakers+microphone to make a 3G Call. Just to clarify, I don't mean using a VOIP client such as skype connected to the internet using 3G. Thanks.
posted by gnujunk to technology (6 answers total)

AIUI, the interface between the 3G modem and the computer isn't terribly standardized, so you'll need to specify what brand/model of modem you're using.

But every cellular interface I've seen treats voice and packet-switched-data as completely different kinds of things. The host computer only sees a pretty high-level abstraction of the cell network. So unless your 3G modem was explicitly designed to let you make voice calls that way, my guess is that no, you can't do that.
posted by hattifattener at 2:18 AM on June 18, 2010

Do 3G phones actually use 3G to make a call? My limited understanding is that data and voice use separate radios and bands.Perhaps you mean "can a 3G modem make a GSM (or other cellular voice network) call?"
posted by zippy at 2:40 AM on June 18, 2010

I've never seen one that can do that. (Most 3g modems can send/receive SMS text messages and that's about it).
I can make calls using my pc soundcard over bluetooth to a phone, so a phone that is also a 3g modem might achieve the desired result.
posted by samj at 2:44 AM on June 18, 2010

Like zippy says 3G is the data connection and GSM or CDMA is the cellular connection. It's like asking if you can make regular phone calls with your DSL modem.
posted by dozo at 6:08 AM on June 18, 2010

"3G" referrs to the Generation of cellular service you're using. Analog "AMPS" is first generation, GSM/TDMA/CDMA is second generation, WCDMA/HSPA/EVDO is third generation. The mere generation of a particular cellular system does not denote whether or not it passes data. All generations of cellular systems up to 3G treat data and voice as separate streams. Voice is circuit switched, data is packet switched. 4G treats data and voice the same, but current 4G phones like the EVO drop down to CDMA for voice calls. Data and voice in GSM/CDMA do not use different modems in currently available cellular telephones. The limitation is by design of the card or telephone, not because of some inherent limitation in the standard specification.

That said, no, you can't use a commercially available '3G' modem of any type (EVDO/HSPA) to make 3G calls. You can use a 3G modem to send text messages. You can use a 3G modem to Skype/SIP/other flavor of VOIP. You can use a 3G phone as designed to call phone normally.
posted by Geckwoistmeinauto at 7:20 AM on June 18, 2010

Actually yes, you can use commercially available '3G' modems to do this, regardless of what previous answers claim. It is true that you can't use any 3G modem, most does not support this (although this is due to drivers often. Many of the 3G chips that are used supports this..)

Here is one USB 3G modem that supports this for example: Huawei K3520. Here is a blog post describing who to enable this on many Huawei modems.

Most branded modems from operators (at least i Europe) are just rebranded Huawei modems, so if you already have a modem you might be able to hack it to support voice calling.
posted by rpn at 8:06 AM on June 18, 2010