Nortel Networks 2750 manual cable pinouts

100Appendix A Technical specifications

3.At each end, the cable shield and connector shell must connect respectively to pin A of the 34-pin connector and pin 1 of the standard 28-pin connector.

4.Do not connect Shield to Signal Ground because these are separate signals.

Table 34 provides the X.21 cable pinouts. (The pair suffix A or B refers to an individual wire within a twisted pair.)

Table 34 X.21 cable pinouts

Standard-wired		Pair number	Standard-wired
end 28-pin male	Signal name	and conductor	end 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	Note 1
9	RXCB	pair 4B	pair 5B	Note 1
24	SCTEA	pair 5A	pair 4A	Note 1
11	SCTEB	pair 5B	pair 4B	Note 1
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	Note 2
22	DSRB	pair 8B	no conn	Note 2
20	DTRA	pair 9A	no conn	Note 2
23	DTRB	pair 9B	no conn	Note 2
8	DCDA	pair 10A	no conn	Note 2
10	DCDB	pair 10B	no conn	Note 2
18	LL	pair 11A	no conn	Note 2
21	RL	pair 11B	no conn	Note 2
25	TM	pair 12A	no conn	Note 2
26	M0	pair 12B	no conn	Note 2
27	M1	pair 13A	no conn	Note 2

NN46110-318 02.01