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Interface Pinouts
83
V.11/X.21 Link Pinouts
The connector shown here and pinouts described here correspond to the connector labeled
“V.11/x.21” on the back of the unit.
DB15 Female DTE
18
9
15
Contact
Number
X.21
Circuits
Reference
Circuit
Name
Direction
To From
DCE DCE
1 Protective Ground NA
2 T (A) Transmitted Data (A) X
3 C (A) Control (A) X
4 R (A) Received Data (A) X
5 I (A) Indication (A) X
6 S (A) Signal Element Timing (A) X
7 ----------
8 Ground Signal Ground NA
9 T (B) Transmitted Data (B) X
10 C (B) Control (B) X
11 R (B) Received Data (B) X
12 I (B) Indication (B) X
13 S (B) Signal Element Timing (B) X
14 ----------
15 ----------
Figure D-6 V.11/x.21 Link Pinouts
The connecting cable must be a shielded cable.
Circuits which are paired (contain an (A) and (B) reference) should be connected to
twisted pairs within the connecting cable.
NOTE For U.K. Approval:
The connecting cable may be any length between 0 and 5M. Each end must be terminated in
a male 15 pin X.21 connector as defined in ISO-4903 1989, but one end of the cable must
have UNC-4-40 screws and the other end must have M3 screws.