Patent ID: 8331356

Claim:
A method for transmitting a signal, comprising: receiving, by a first node, a Global Text Telephone (GTT) signal; sending, by the first node, the GTT signal encoded in a Cellular Text Telephone Modem (CTM) format to a second node, if determining that transmission between the first node and the second node is based on an Internet Protocol (IP) network; wherein the GTT signal is a service message that comprises an identifier of the GTT signal in the CTM format, wherein the identifier indicates that the GTT signal transmitted between the first node and the second node are in the CTM format; wherein the first node is an end office of mobile services, the second node is a gateway office, and the sending, by the first node, the GTT signal in the CTM format to the second node comprises: determining, by the end office of mobile services, that the received GTT signal is in the CTM format, and sending the GTT signal in the CTM format to the gateway office; wherein the method further comprises: determining, by the gateway office, an encoding format of the GTT signal according to the identifier of the GTT signal in the CTM format; determining, by the gateway office, whether transmission between the gateway office and a third node is based on a Time Division Multiplexing (TDM) network, wherein the third node is a next hop of the GTT signal; and if the transmission between the gateway office and the third node is based on the TDM network, converting the MT signal in the CTM format into a GTT signal in a format of the international text telephone modem standard, wherein the format of the international text telephone modem standard comprises V.21, EDT, Bell 103, V.23, DTMF, V.18, and Baudot.