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Choppy sound quality. Connecting IP phone directly to modem.

Hi, I'm trying to setup a Yealink IP phone. The phone registers and everything works. The only problem is very choppy sound quality - even when the phone is the only device connected to the router.

The Yealink comes with a built-in router. So I thought I would go that route and connect it directly to the cable modem. I tried that and the phone can't pull an IP address. I called Brighthouse to see if there was anything they could do. She reset the modem from her end. The phone still couldn't pull an IP. She then said that the modem isn't meant for VOIP and I would need to buy a modem/router combo.

Does that sound right? Can you not connect an IP phone directly to a cable modem? The Yealink's manual doesn't specify that one way or the other. With it acting as a router though, you would think it could. I read that Brighthouse has their issues with IP addresses and multiple devices and mac addresses. Are there special instructions I need to give the Brighthouse rep - to get the phone to pull an IP address?

I ran a line quality test and everything passed: »/pingtest/572b ··· /2976042. It's standard Roadrunner service. The equipment is about 7 years old:

Modem: Toshiba PCX2500
Router: Belkin F5D8230-4

Any suggestions are appreciated. Thanks!

grand total

If you haven't already tried this, try powering down the modem, disconnecting your current router, then power up the modem and connect your phone.

Does your current router get a public WAN address at the moment?
DPC3825 (bridged mode) - WRT610N + Tomato - Panasonic KX-TGP500 - Asterisk 11.0.2 on Virtual Server
Anveo - FreePhoneLine - Voxbeam - Numbergroup - Callcentric - VoIP.MS - Localphone - UKDDI


reply to idbit
said by idbit:

The only problem is very choppy sound quality - even when the phone is the only device connected to the router.

When doing this test, confirm that the router's Wi-Fi is disabled, or that no clients are associated.

Do you get choppy sound when using another IP phone, ATA, softphone or smartphone app to connect to your provider?

Do you get choppy sound when using the Yealink to connect to a different provider? If you don't have one, a free Callcentric account should suffice for this test.


reply to idbit
Thanks for the help guys. This is embarrassing. I had my LAN cables mixed up. So now the phone works fine feeding off the modem. Now the only problem is getting my computer to connect to the internet - feeding off the Yealink's router.

When I click the Network Status icon in the systray, the reported IP address doesn't match the IP address shown on the Yealink phone. I'm assuming all that stuff should match, shouldn't it - the IP, gateway, subnet mask?

Right now, I have everything connected the old way so I can post here. I'm going to go back now and hook the phone back up to the modem, so I can try a few different things to get the computer connected thru the Yealink's router.

Thanks again.


reply to idbit
I wanted to update this old thread. I had a really hard time getting my computer to connect to the internet when feeding off the Yealink's built-in router. After trying a lot of different things, I finally solved it.

The problem was with one of the Yealink's default settings. In the network settings for the router, you can set the beginning and ending IP range for the PC connection. The default setting for beginning IP was: So the computer took that IP: The problem is that is also the IP address of the router itself, so they conflict. I had seen that early on and thought that was okay. I thought the two IP's were actually supposed to match. Eventually, somebody set me straight. So in the Yealink's network settings, I changed the beginning IP for the PC connection to: The computer then took on IP and everything was fine after that.

Maybe there was something I did wrong that caused the Yealink router to assign its own IP as the beginning IP for the PC connection. Maybe not. But if anybody is having problems connecting to the internet using the Yealink router, this might be the problem.


Saint-Hubert, QC
How about the choppy calls, do you still have this issue?


said by Dan_voip:

How about the choppy calls, do you still have this issue?

The phone is working great now. It's connected straight to the cable modem. Nothing else is using the network besides the phone and the pc connected to its lan port. This is my first VOIP experience. So I'm loving it. Everything is so instantaneous. The phone is great. The sound quality is great. The configuration possibilities are crazy.

I'm also really impressed with how quick the phone is to reboot whenever I change the network setup. At first, I was going back and forth between connecting the Yealink directly to modem and connecting the Yealink to my old router. Every time I would do that, the IP assigned to the phone would change. So I would have to reboot the phone. All the times I rebooted, I never had a problem. It would start up, accept its new IP and network config, and just work, all in a matter of a few seconds. I must have gone through that drill 30 or 40 times and the Yealink never blinked. I don't know if that's typical for SIP phones. But from my experience with anything related to networks, things usually aren't that easy.