DIF101 - X.21 Interface
Connector: DB15F
Pin # Signal Description
1 fg frame ground
2 t(a) Transmit data A (output)
3 c(a) Control element A (output)
4 r(a) Receive data A (input)
5 i(a) Indicator element A (input)
6 s(a) Timing element A (input)
7 b(a) Byte timing A (input)
8 sg Signal Ground
9 t(b) Transmit data B (output)
10 c(b) Control element B (output)
11 r(b) Receive data B (input)
12 i(b) Indicator element B (input)
13 s(b) Timing element B (input)
14 b(b) Byte timing B (input)
15   No Connection