ATL Telecom AM2048 - Manual (Page 34)

ascom
telecom USER GUIDE AM768A/AM2048A
34
Issue 8
5.7.2 X.21
V11 refers to ISO 4903 for the connector pin-out.
Circuit
Interchange Circuit Name Pins
A…..B Definition
G Signal ground or Common Return 8
T Transmit 2 9 From DTE to DCE
R Receive 4 11 From DCE to DTE
C Control 3 10 From DTE to DCE
ON during Data
OFF during Control
I Indication 5 12 From DCE to DTE
ON during Data
OFF during Control
S Signal Element Timing 6 13 From DCE to DTE
T and R change at
OFF to ON of S
B Byte Timing 7 14 From DCE to DTE
OFF for the ON period of S
During the last bit of the octet
X DTE Signal Element Timing 7 14 MK I, not used.
MK II, From DTE to DCE
The clock rate is set up using the “Configuration > User Port” Menu.
Select the required value of N for Nx64K circuits.
DTE – DCE mode, and X-B mode are selected using the hardware links on the X.21 interface module.
Note: X-B is only available on the X.21 MK II Plug In Module.