<div>Ravi,</div> <div> </div> <div>I would suggest the use of a good echo cancelling platform too. Look at your echo cancellers characteristics. The important things to look for are compliance to the G.168 standards and a good echo tail - 128ms is good or sometimes quoted in taps - 1024 taps is good.</div> <div> </div> <div>International calls have a longer delay for the voice to echo back - this delay is what the taps/echo tail have to work with. Some cheaper echo cancellers have very short tails - 16ms, which may be sufficient to handle echo on national networks, not on international network connections. Cellular networks can also have longer delays.</div> <div> </div> <div>For example Digium PRI hardware (there is a new card coming out soon that is better) has a short echo tail, where as Sangoma PRI cards have a long (128ms) tail. Quintum gateways also have echo cancellers with 128ms tails.</div> <div> </div> <div>Choose your hardware for
connectivity to the PSTN carefully - it can have dramatic effects on voice quality.</div> <div> </div> <div>Neill....;o)<BR><BR><B><I>Evan Borgström <evan.borgstrom@ca.mci.com></I></B> wrote:</div> <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid"><BR>Just because you're sending both calls through the same gateway doesn't<BR>mean that your providers upstream gateways don't change depending on the<BR>destination. Your provider could have tens or hundreds of different<BR>vendors depending on where they terminate calls.<BR><BR>Check the ECAN (echo cancellation), VAD (variable audio detection), etc<BR>settings on your ATA or IP phone. Play with the gains (turing down the<BR>tx gain on the microphone can help). Try changing codecs. Buy a book on<BR>how PSTN audio works or speech codecs, do some google searches, there's<BR>LOTS of info out there.<BR><BR>-Evan<BR><BR>ravi reddy wrote:<BR>> Thanks for your
reply<BR>> <BR>> Here both local calls and international calls are passing<BR>> through same gateway but why iam hearing echo only for international calls<BR>> <BR>> can you have any idea please suggest me<BR>> <BR>> Thank You<BR>> <BR>> Regards,<BR>> Ravi<BR>> <BR>> On 7/10/06, ravi reddy <MRAVIKREDDY@GMAIL.COM>wrote:<BR>>><BR>>> Hi users<BR>>><BR>>> I noticed some strange thing yesterday when i made a SIP-SIP<BR>>> call everytthing was O.K , when I made SIP-Pstn local call its pretty<BR>>> good<BR>>> BUT When I made SIP-PSTN (international) I am Hearing my Voice back at<BR>>> Some<BR>>> stages , I tried for lot of calls but i dont understand where actually<BR>>> the<BR>>> problem is creating ,<BR>>><BR>>> Can any body please solve this "ECHO" problem<BR>>> Thanks.<BR>>><BR>>> Regards,<BR>>> Ravi.<BR>>><BR>> <BR>> <BR>>
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