Method and apparatus for transmitting signal

The embodiment of the invention provides a method and apparatus for transmitting a signal. The method includes: receiving a first signalling conforming to a first network protocol and sent by a first device, wherein the first network protocol is a protocol supported by a network where the first device is located; converting the first signalling into a second signalling conforming to a second network protocol, wherein the second network protocol is a protocol supported by a network where a second device is located, and the first network protocol is different from the second network protocol; and then sending the second signalling to the second device, wherein the first device is either user equipment or a program-controlled switch, the second device is the other of the user equipment and the program-controlled switch, the protocol supported by the network where the user equipment is located in real-time transmission protocol RTP, and the protocol supported by the network where the program-controlled switch is located V5 protocol. The method and apparatus can realize the communication of a whole network system when the network transformation at the user equipment and the program-controlled switch are not synchronized.