Symptom
After the PSTN user calls the intra-office user through the FXO port on the IAD, echo and noise occur during the conversation between the two parties.
Possible Cause
The possible causes are as follows:
- The PSTN signal is poor.
- The IAD is grounded improperly.
- The IAD software parameters are configured incorrectly.
- The IAD software has defects.
Solution
- Connect the PSTN line
directly to the phone and check whether the voice quality is good.
- If no, it can be concluded that the fault is caused by the PSTN network.
- If yes, go to Step 2.
- Verify
that the IAD is grounded properly by referring to 3.11 "AT0 Ground Impedance
Test." Check whether the fault is rectified.
- If yes, the procedure ends.
- If no, go to Step 3.
- Re-configure the EC, dsp, and pstnport parameters on the IAD.
Check whether the fault is rectified.
- If yes, the procedure ends.
- If no, go to Step 4.
Configure the EC, dsp, and pstnport parameters by referring to the IAD product documentation.
- Upgrade
the IAD to the latest version. Check whether the fault is rectified.
- If yes, the procedure ends.
- If no, go to Step 5.
- Contact your service provider for assistance
