I hope someone has someone can help with an ongoing issue we have been experiencing over the past months. I have an Elastix box configured and setup with Polycom 331 soundpoint phones (both on the LAN and in remote office over the internet). My intent is to use the box purely with a SIP provider for calling in/out of the office. Sadly we can only achieve about 85% stability with call quality (garble) or drop calls occurring the remainder of the time and in an unpredictable manner. I have tested with 3 different SIP providers using both sip and iax2 connections. What is interesting is that we can have simultaneous calls on the system and whereas one might become garbled the others are okay. The effected calls always seem to involve the SIP line while direct phone-to-phone calls never seem to have an issue (even if one phone is remote). In fact- I have even had a situation where within a conference room with 3 outside callers dialed in through the SIP provider one caller becomes garbled and all the others remain fine. It seems like if it were simply a network problem everyone would be effected. I am connected via. Verizon FIOS 25MBs up / 25MBs down using there standard issue westell modem. I have -- as best I can tell-- disabled SPI and any other firewall issues on the modem. Most calls are ulaw but g729 (free codec) yields similar results. Setting any level of jitter buffering seems to make things much worse. And as I say the system works great 85% of the time. I am about to abandon SIP and order a digium card and install a batch of analog lines. I hate to do it... but this has got me stumped. Thanks for ANY suggestions!