Dears,i need to be notified when i call some one and he already have other call.so i need to know that i am on waiting

Dear Sir,i installed primacell to my VG router it is working MGCP with the call manger 10.5 and the caller id of the inbound calls show as O the below the configuration of the port that are connected to the primacell:voice-port 0/1/3 cptone EG timing...