Abstract: The present invention provides a method for synchronizing call signaling and voice circuit setup in a telephone call between an initiating and destination PSTN switch passing through a packet switched network. The packet switched network has Media Gateways (MGs) that interface with the PSTN switches through voice trunks, and Media Gateway Controllers (MGCs) that control and instruct the MGs. The PSTN switches send Signaling System 7 (SS7) call signaling messages to each other through the MGC. To synchronize the call signaling and voice circuit setup, the MGC delays the effect of these SS7 messages until the MGs are initialized using Media Gateway Control Protocol (MGCP) commands. This delay is achieved by modifying the messages from the initiating switch, by imposing some requirements for the destination switch, such that the destination switch is forced to delay seizing the voice trunk from its side until further commands are sent from the MGC.