Disturbed or absent free tone with telephone operators using Patton routers

When you receive the service from alternative telephone operators, who use Patton routers, making a call, sometimes the free tone you hear when sending an outgoing call can be perceived as disturbed or completely absent.

To overcome this problem, the telephone operator must enable the Early Proceeding function on his router (Patton).

This way the router will ignore “183 progress” SIP packets without “sdp”.