Nortel Networks 1750 manual Appendix a Technical specifications, cable pinouts

94Appendix A Technical specifications

The following table provides the X.21 cable pinouts. (The pair suffix A or B refers to an individual wire within a twisted pair.)

Table 33 X.21 cable pinouts

Standard-			Standard-
wired end		Pair number	wired end
28-pin male	Signal name	and conductor	15-pin male	Notes
2	TXDA	Pair 1A	2
14	TXDB	Pair 1B	9
3	RXDA	Pair 2A	4
16	RXDB	Pair 2B	11
15	TXCA	Pair 3A	6
12	TXCB	Pair 3B	13
17	RXCA	Pair 4A	Pair 5A	Wires of pair 4 connect to
				wires of pair 5, but not to
				pins in the DA-15.
9	RXCB	Pair 4B	Pair 5B	Wires of pair 4 connect to
				wires of pair 5, but not to
				pins in the DA-15.
24	SCTEA	Pair 5A	Pair 4A	Wires of pair 4 connect to
				wires of pair 5, but not to
				pins in the DA-15.
11	SCTEB	Pair 5B	Pair 4B	Wires of pair 4 connect to
				wires of pair 5, but not to
				pins in the DA-15.
4	RTSA	Pair 6A	3
19	RTSB	Pair 6B	10
5	CTSA	Pair 7A	5
13	CTSB	Pair 7B	12
6	DSRA	Pair 8A	No conn	The term No conn means
				the wire does not connect
				to a pin in the 15-pin
				connector.
22	DSRB	Pair 8B	No conn	The term No conn means
				the wire does not connect
				to a pin in the 15-pin
				connector.

NN46110-316 03.01