Asterisk voice quality problem

hello
i`m using an ovenvox E1 card for a call center
operator are Complainant becuase of voice quality
during a conversation sometimes voice be droped and they cant understand what sayed another person on the conversation
another problem is that they say me sound volume is low
what should i check and what parameters are important?
can anyone help me?
thank alot

Contact the company that sold you that card.

you mean there is no any option to change voice volume or quality?
i mean rxgain and txgain or any other option if there is
please explane the configurable option in asterisk for this pepose
thank you

txgain and rxgain are explained in chan_dahdi.conf.sample.

However your description of the problem suggests that it is worse than simply the wrong gain. On the limited information available, it is likely that you are getting hardware buffer overruns, or you have a faulty line card. These are things that need fixing in the hardware, and need knowledge that may only be available to the hardware vendor.

As this is an E1 interface, you may have problems on the line side of the hardware, as well, e.g. timing slips, an inadequate eye, or a line coding mismatch.

Incidentally, you should never need to vary the gain on an E1 interface, as the gain setting should be done at the analogue network boundary. I’m not sure that I would expect txgain and rxgain to work on such interfaces.

[quote=“david55”]txgain and rxgain are explained in chan_dahdi.conf.sample.

However your description of the problem suggests that it is worse than simply the wrong gain. On the limited information available, it is likely that you are getting hardware buffer overruns, or you have a faulty line card. These are things that need fixing in the hardware, and need knowledge that may only be available to the hardware vendor.

As this is an E1 interface, you may have problems on the line side of the hardware, as well, e.g. timing slips, an inadequate eye, or a line coding mismatch.

Incidentally, you should never need to vary the gain on an E1 interface, as the gain setting should be done at the analogue network boundary. I’m not sure that I would expect txgain and rxgain to work on such interfaces.[/quote]

thank you david55
i will tel my vendor,can you suggest me about best vendor for E1 card? in my country there are sangoma,atcom,open vox
which one is better in you idia? it is force to buy hardware echo canceller?
and at last,is`nt there any option to edit or monitoring to find that problem is from card or my my configuration?