Abstract: In a communication network having multiple transmission channels, digital data comprising messages sufficiently short to be treated as packet messages are not sent over the network channels ordinarily used for message transmission, but instead are sent over network channels typically used for out-of-band signaling. Each data message is prepared and its length is checked for suitability as a message packet. If the data message can be packaged as a message packet, it is sent over the flat rate network channel. If the message cannot be packaged as a message packet, then it is sent according to conventional message transmission techniques for the network. The channel selection scheme can be implemented in a system that utilizes the Integrated Services Data Network (ISDN), such that data messages are checked to determine if they can be sent over the ISDN D channel rather than over the more conventionally used ISDN B channel.