When interfacing between Asterisk and the PSTN many problems can arise, you can debug your PSTN interface.

Echo

Signal Level

• ztmonitor <channel number> -v
  • gives you a visual representation of the sound strengths and makes it easy to see if the receive or transmit signals are too high or out of balance

Randomly Dropped Calls

• Read comments in zapata.conf for the callprogress setting.
• Try setting busydetect=no or greater than 6

How to speak Telco

Linemen and installers have to debug wierd line situations all the time. Accordingly they've built testing facilities on to specific lines so they can debug echo and so on. Take a look at http://www.nettwerked.net/K-1ine_37.txt. Pay careful attention to Quiet Termination and Milliwatt test lines - you will need to get friendly with a telco field person to find out the access numbers at your serving Central Office.

_Nahid

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Asterisk