Why EDGE/GPRS data gets disconnected when Call Comes on Mobile?

By KiranNokia ·
Hello Team,
Got a doubt here. I have seen that when ever i am using the packet data connection (GPRS/EDGE) on mobile and if a Voice Call comes, the Package data will be stopped and once the call gets disconnected it will resume sending the data.
For 3G Data the same is not happening, at the time of voice call it will continue sending the Packet data.

Also observed that at some location GPRS/EDGE Data still continue while Voice Call in progress.

So totally confused what is this logic behind. Can some one tell me what's happening here ?

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All Answers

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Well I'm not 100% sure

by OH Smeg Moderator In reply to Why EDGE/GPRS data gets d ...

But at a guess I would say that this has something to do with the Data Transfer speed of the device and the current connection.

If the Data Transfer speed is down then when you get/make a Voice Call it stops the Data Transfer to free up bandwidth for the Voice Call, then when the Voice call is finished it continues the Data Transfer.


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This depends on device class

by robo_dev In reply to Why EDGE/GPRS data gets d ...

EDGE (and GPRS) are capable of supporting simultaneous voice and data ONLY if it is a Class C device.

Most phones these days are Class B (such as iPhone).

Class B support voice calls while in data mode (data disconnects when a call comes in) and data is "attached" while the phone is idle. Some Class B devices are configured so that the data takes priority (iPhone). Thus an iPhone will not take a call when an active edge data transfer is goes to voicemail.

Class A devices are either in data mode or voice mode (but never both).

The priority of voice vs data is set by the carrier, so perhaps what you describe is that you have a Class C device and some towers are configured differently from others.

Don't forget too that sometimes things like web pages are cached on the device, so what 'looks like' data transfer is just loading from cache, or things like updating an email inbox happens a long time after the actual email data has been transferred to the device.

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My Observation

by KiranNokia In reply to Why EDGE/GPRS data gets d ...

I have observed that when i am on 3G network with the same phone, i can access both data and Voice at a time, it never disconnects the data when a voice call is active.

Also when i am travelling, at some places, i have seen i can access both GPRS/EDGE Data and Voice Calls. Also its not operator dependent, i have used many operator SIM and tried to access DATA and Voice at a time. Some place it will work both and at some places DATA will disconnect when Voice Call in Progress.

I will not get a proper reply for this query if i ask to the Operator Customer Care i am sure, So I thought I will better post it here only... :)

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I am guessing that this may be 'tower dependent'

by robo_dev In reply to Why EDGE/GPRS data gets d ...

Many phones have a 'super secret' diagnostic (field test) mode that would probably show you the technical details of the data/voice capabilities of the cell site or tower your phone has made the connection with.

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This is a handset/network limitation

by craig In reply to Why EDGE/GPRS data gets d ...

Hi there,

You are right that you won't get an accurate answer from the customer service team at your provider, this is a question well out of their league.

The answer lies in the use of the radio equipment in the phone, someone from a hardware background might be able to give you a more technical response however I will try to explain in basic terms from my recollection (I worked in tech support for a mobile provider for several years).

The handset uses hardware which connects to the network, these are radio transmitter/receivers. All handsets use a 2G radio for voice and GPRS/EDGE data, 3G handsets have a separate radio as the technologies and frequencies are different.

When you make a voice call, the 2G radio is in full time use as the handset makes a circuit switched connection, this leaves no capacity for GPRS/EDGE packet data. 3G uses packet switched data using the separate 3G radio, this is why you can still use 3G data whilst making a voice call.

The other reason is that the network will only allow one connection of each type from the handset, this is primarily to prevent handset cloning but is also used for billing and authentication purposes.

Some handsets and networks are offering voice over 3G now (although the feedback I have heard has not been great), this in theory would mean you could make a call and use data on the same kit as both would be packet switched, of course if you were to use a lot of data this would affect the bandwidth available for voice calls, normally ATM would be used to give the voice packets priority, as I no longer work in the indusrty I am not up to speed on the latest developments.

I hope this helps.


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