APPENDIX D
DB-15F Connector-DCE Setting
(X.21 Interface)
Pin #
Signal
1 . . . . . . . . . . . . Frame Ground
2 . . . . . . . . . . . . T (Transmit Data-A)
3 . . . . . . . . . . . . C (Control-A)
4 . . . . . . . . . . . . R (Receive Data-A)
5 . . . . . . . . . . . . I (Indication-A)
6 . . . . . . . . . . . . S (Signal Element
Timing-A)
7 . . . . . . . . . . . . BT (Byte Timing-A)
8 . . . . . . . . . . . . SGND (Signal Ground)
9 . . . . . . . . . . . . T/ (Transmit Data-B)
10 . . . . . . . . . . . C/ (Control-B)
11. . . . . . . . . . . . R/ (Receive Data-B)
12 . . . . . . . . . . . I/ (Indication-B)
13 ........................S/ (Signal Element
Timing-B)
14 .......................BT/ (Byte Timing-B)
Note: X.21 uses balanced data and control signals.
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