Voice Over IP

V.24

V.24 is used on the vast majority of modems to describe the functions of the interchange circuits ("pins" or circuits) on the interface. Many products use this standard, principally in modems, line drivers, multiplexers, and digital service units. The V.24 interchange circuits are listed in Table 6-1, with a brief description of their functions.

Figure 6-3. Physical connector examples

Table 6-1. Interchange Circuits

Interchange Circuit Number	Interchange Circuit Name
102	Signal ground or common return
102a	DTE common return
102b	DCE common return
102c	Common return
103	Transmitted data
104	Received data
105	Request to send
106	Ready for sending
107	Data ...