1-Way Speech on outbound calls

SJ1252Boom
SJ1252Boom Posts: 2  Freshman Member

I've got a SIP account registered on a Zyxel vmg8623-t50b. Inbound calls work perfectly but I'm getting one way speech on outbound calls, the person I call can hear me but I can't hear them, my VoIP provider say's it's an issue with the router settings. They've recommended that the RTP ports should be set to 35000 to 65000 but it looks like I cant set that range. If suggestions would be greatly welcomed

Consumer Product Help Center