atcomsystems.ca/forum Forums TDM Business Telephone Systems NEC Telephones & Systems CCIS - Whats considered "good" between sites

I've entered that water between a phone system and IT...called CCIS.

I have two sites, A & B. When A calls B everything is great, call quality is clear/concise, nothing drops, ever call hits its mark every time...AND HOW!

B calls A...the transmission to A is fine but the audio received by B is garbled, Burger King drive thru quality...

Ping results between sites using -l 1500 and -t for continuous show a spike in MS every 40 mins or so. It goes from 43ms, 52ms, 46ms, 50ms, to 8332ms, 7559ms, then back 53ms, 47ms...etc etc

is a ping between sites reliable? If not, what other tools are available?

What systems are they?
Ping times are a good indicator of the quality of the link. Have you performed the ping from A to B and again from B to A?
What is the CODEC on both directions?
Are the data switch ports set up the same way for both locations?
What is the WAN medium? Fiber, DSL? I worked a site with IP phones that had DSL. It simply would not work consistently. Phones rebooted at random and dropped calls. They went back to a stand a-lone key system at that location. One of 15 in an IP phone network. (NEC UC3).

Just a guess, but possibly a network port at one end is stuck in half duplex mode.

If this is CCIS over IP then hard code 100/full duplex on both sides and remove spanning tree.

D

Also, if CCIS/IP make sure QOS is set to 5/7 or higher and that switches in the network support QOS.

Could also be an issue with network traffic at the affected end... Look for bandwidth issues on the DSL/ADSL/FIBER at that end.

Voice packets are UDP, so you may want to check firewalls to make sure that UDP packets are permitted to pass through.

Just had a similar issue with SL1100 slnet'd with 3 sites. We were only having issues at 1 site. After some digging we found that the internet connection at that particular location was having issues, dispatched ISP, they rebuild the modem config and boom call quality was good again. We found this by ping all 3 sites public IP address and were getting consistent ping times at 2 sites but the problem site would timeout and never consistent. The ISP looked at it after we found it and that is when they dispatched a tech for the modem.

Not saying this is your problem as there are lots of things to take into consideration but wanted to share incase our solution would help you.