[Q] No Sound when calling certain numbers

I have this crazy issue with my D2G. I have had a similar issue in the past with all my android phones. It was worst with my SG2. It has not really been an issue up to now with my D2G but it is getting worse.

What happens?

When I call certain numbers there is no Audio in either direction, the call timer counts up and the call is in progress, just no sound in either direction. If the affected number calls me back, the same thing happens.

Which numbers are affected?

Only other mobile numbers. Always the same numbers. Always the same result. It was just an occasional mobile number, perhaps one in a hundred, but in the last couple of days BOTH of my gfs numbers are doing this and she has 2 separate numbers one attached to a D2G and one on a Samsung flip phone.

What have I tried?

Switch between Clean stock Froyo & Stock Gingerbread. Factory Reset, Wipe Cache, Wipe Dalvik Cache. Power Off Phone. Pull Battery. Nothing makes any difference.

If I pull my SIM from my D2G and place it in any other phone, the SAME thing still happens! If I swap the SIMS between 2 affected phones and try, it still happens.

**If I pull the SIM from my D2G and place it in an old Hermes I have lying around calls work perfectly in both directions.**

What works?

Calls to all landlines and most mobiles. Calling a number from the phone using GV or Skype.


Is there any pattern to the destination numbers?

Affected phones are all different brands and carriers, no pattern identified.


Thoughts so far:

It can not be the SIM card as it works in some phones.
It can not be the System version or Radio Firmware version as I get the same issue with Gingerbread and Froyo.
It can not be the cache or any settings specific to my phone.
One of the phones must be an android device.


***Ok, in testing now I just found the problem. If I have the phone set to UTMS then there is no Audio if the other phone is also a UTMS device, but it works fine if the other phone is GSM. If I have the phone set to GSM all calls work all the time to all devices.

The issue is calls between UTMS phones.

At least now I know i can always make/receive calls if I select GSM, I still want to find a solution though.

I am on the Telstra 850Mhz UTMS network in Australia.

Please read the detailed post I made and don't post unless you understand what it implies. If you are having no sound problems because you have the volume turned down or mute enabled or you have a bluetooth bug, this has nothing to do with the issue that I have.

I have some kind of low level issue, my guess is that it is something to do with the codec selection based on the network transport type. The fact that the issue is there between 2 phones, then just changing to new Sim cards to identical carrier cards with different phone numbers, removes the issue suggests that the network is storing some information about the numbers. The fact that switching the D2G to GSM makes it work, suggests that the GSM codec is not affected.

I have my phone in GSM mode and now I can make and send all calls, but my data is so slow.

Is there a way I can force the phone to use a specific codec and stay on UTMS?

Ok, so I suspect it is the codec.

I found how to access the programming menu

On the phone's dail pad, enter:
##PROGRAM
Passcode is 000000

Most of the settings are for CDMA, under Test I can change the codec, I'll try some tests.

If anyone knows how to change the default codec let me know!

OK, I found the instructions on Droid Forums..


Pull up the dialer on your phone
Dial ##PROGRAM (##7764726)
Hit Send (the call button)
The password is 000000 (six zeros)
Select "Option 6 - Test Mode"
Hit "Next" until you come to the "Field test screen"
Under "Service Option" (top most), select EVRC-B
Hit "Back"
The phone should then reboot and you'll be all set.

OK, it seems all these settings are for CDMA, I can't find a way to access the GSM settings yet.

Ok, I am still working on this issue. I figure that if there is some way of changing the default UTMS codec to be the same as the GSM that might work. I am still trying to find the setting for this. However I was looking through the build.prop and I found some settings that seem to have an effect on other issues that I notice.


If you edit build.prop and change the line

ro.mot.phonemode.vzwglobalphone=1

to

ro.mot.phonemode.vzwglobalphone=0

then reboot the phone

The phone behaves slightly differently, the signal strength indicators are more accurate for a start.

Also from what I can see the following options are set to Verizon defaults and are only useful for people on the USA and so should be changed for overseas users..

ro.telephony.gsm-routes-us-smsc=0
ro.cdma.home.operator.isnam=0
ro.telephony.default_network= (set to 7 for global, change to 3 for Gsm/UMTS or 4 for CDMA only)
ro.cdma.nbpcd
keygaurd.no_require_sim=false

The problem continues to get worse. More and more numbers get no audio either when they call me or when I call them. It only happens on the WCDMA 850mhz Telstra network.
The phone behaves normally on any other network or on the GSM Telstra network.

Re-flashing the phone with Miui or CM7 or CM9 or any of the official Motorola firmware's makes no difference. It is a truly crazy problem.

I am going to buy another android phone from Telstra and see if that behaves normally with my sim card. A non android phone I have behaves normally.

The behaviour is still the same, if I am on 3G WCDMA 850mhz on the Telstra network, someone calls me or I call them, it shows the call is connected, neither of us gets any audio, no hash, just silence. Rebooting the phone, changing the rom, factory resets, changing the Telstra SIM, nothing makes any difference. Switch to GSM only and suddenly the issue goes away.

My GF also has a D2G and has exactly the same issue and it is getting worse for her too.

I am guessing that the network is storing something like the phones IMEI on the WCDMA network and then forcing an incompatible audio codec. I don't know enough about the operation of the network to be able to prove anything.

I would like to find some way to force or change the audio codec that gets used when I make calls, is there any way to see what the phone is using for each call?

Ok, another update. I have been doing some more testing. I have discovered that DTMF tones go through to a non Android Telstra phone . Any key presses on the D2G can be heard as DTMF tones on the other phone. DTMF tones do not register on the D2G.

Between two D2G phones on the 850mhz wcdma network there is no audio in either direction and the DTMF tones do not come through either.

As usual switch either phone to GSM and everything works perfectly again.