Black Box Series 5000 Reference Manual page 35

The connector shown here and pinouts described here correspond to
the connector labeled "V.11/X.21" on the back of the unit.
X.21
Contact Circuits
Number Reference
1
2 T (A)
3 C (A)
4 R (A)
5 I (A)
6 S (A)
7
8 Ground
9 T (B)
10 C (B)
11 R (B)
12 I (B)
13 S (B)
14
15
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 should be manufactured from Belden Cable, or a cable with equivalent specifications.
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. The cable may be any length
between 0 and 5M.
V.11 & X.21 Link Pinouts
8
15
DB15 Female DTE
Protective Ground
Transmitted Data (A)
Control (A)
Received Data (A)
Indication (A)
Signal Element Timing (A)
----------
Signal Ground
Transmitted Data (B)
Control (B)
Received Data (B)
Indication (B)
Signal Element Timing (B)
----------
----------
Figure 3 – 8 V.11 Link Pinouts
35
Link Interfaces Reference
1
9
Circuit
Name
Direction
To From
DCE DCE
NA
X
X
X
X
X
NA
X
X
X
X
X