I have a Huawei E160E and a Huawei K3765 "GSM"-modem.
The question is: How to send and receive audio data placing or receiving phone/ voice calls with those modems?
Both seem to support voice calls, according to specifications (E160E, K3765) and according to AT-commands:
Issuing
AT^CVOICE?
results in
^CVOICE:0,8000,16,20
OK
(both modems the same).
Both modems provide 3 USB ports, I will call them /dev/ttyUSB0
, /dev/ttyUSB1
, /dev/ttyUSB2
(assuming there is no other USB serial device present in the system). The K3765 additionally registers an cdc_ether
ethernet device. I am using Linux.
On both /dev/ttyUSB0
and /dev/ttyUSB2
I can place AT-commands and receive their answers; additionally, /dev/ttyUSB2
reports status messages (like ^RSSI:23
, ^BOOT:38021325,0,0,0,77
, ^SIMST:1
or ^SRVST:2
). The K3765 also reports by default when there is someone calling (RING
), the E160E does not.
On both modems, I can place calls with ATD<number>;
and I can pick up calls with ATA
.
/dev/ttyUSB1
seems to do nothing; simply writing to this file will get no data into it, reading from it gets no data out.
How is it possible to get audio data in and out of the modem(s)?
I already found this stackexchange question and the answer by Sai Chaitanya as well as the comment to use ffmpeg
/ffplay
. ffplay
just stalls for me, and with the code snipped I can not make too much to try it out (not a programmer, and expecially not in C
, though; and don't know if this applies to my modem(s) at all).
In the internet I do not find information on how to actually get audio in and out of those devices, other than using big software packages (asterisk, for example) -- which I do not want, the question is on how to get it to work the basic way.
So, how does audio communication work with (those) Huawei GSM modems?
Modem information: Output of ATI
-command:
E160E:
Manufacturer: huawei
Model: E160X
Revision: 11.609.10.02.432
IMEI: 354765038021325
+GCAP: +CGSM,+DS,+ES
OK
K3765:
Manufacturer: huawei
Model: K3765
Revision: 11.126.03.06.00
IMEI: 353142047899771
+GCAP: +CGSM,+DS,+ES
OK