Hi Jamz.

Are you behind a router/firewall at all? It's certainly not a bandwidth issue on a 10meg connection!

Most of the time issues arise because of NAT problems.

First off check your softphone settings:

For the default proxy settings, fill in the [Default] page to say....

Enabled: Yes
Display Name: YOURDETAILS
Username:YOURDETAILS
Authorization User:YOURDETAILS
Password:YOURDETAILS
Domain/Realm: YOURDETAILS
SIP Proxy: YOURDETAILS
Out Bound Proxy
Use Outboud Proxy: Never
Send Internal IP: Default
Register: Always
Voicemail SIP URL
Forward SIP URL

Once that is done, click on "BACK" twice to get to the "System Settings" page.

Double click Network and set it to be.....

Auto Detect IP: Yes
Listen on IP
Use X-Nat to Choose SIP/RTP Ports: Never
Listen SIP Port: 5060
Listen RTP Port: 8000
NAT Firewall IP
Out Bound SIP Proxy
Force Firewall Type: (do not force firewall type)
Primary STUN Server: YOURDETAILS
Secondary STUN Server: xten.net
Primary DNS Server
Secondary DNS Server
Provider DNS Server: dns.xten.net

Which router are you using? What i suggest you do is vist: http://www.portforward.com/

Look up your router there and forward the following ports to your local ip address:

3478, 5060 and 8000~8005 all UDP

These may vary, so to be sure contact your service provider!

Hope this helps.

Matt