Specifications

Frame Relay Cabling
Cabling Summary A-5
X.21 Port Connectors
The X.21 ports use DB-15 female connectors (DCE type according to ISO 4903).
(Refer to Table A-9.)
TableA-9 Pinouts for X.21 DB-15 Connectors
Pin No. Name Signal Function Polarity Signal Source
2 TA Transmit Data + DTE
9 TB -
4 RA Receive Data - DCE
11 RB -
6 SA Clock + DCE
13 SB -
5 IA Indication + DCE
12 IB -
3 CA Control + DTE
10 CB -
8 SG Signal Ground
1 FG Frame Ground