RAD Data comm ASM-20 - Manual (Page 61)

ASM-20 Installation and Operation Manual Appendix C IR-X.21B Interface Module
EXT Mode C-3
JP 2
INT/RCV
IN
T
/RCV
clock setting
EXT
clock setting
Connector DB-15
EX
T
Figure C-3 Location of Jumper JP2 in the IR-X.21B Interface Module
C.4 EXT Mode
This mode is used in applications of X.21 networks where the system timing is
provided by the X.21 network. The IR-X.21B module has internal buffers to
compensate for the phase delay introduced to the system by the line delay
between the two modems. The buffers are 16-bit FIFO’s connected as shown in
Figure C-4 . When the modem’s clock mode is EXT, the JP2 jumper must be set to
EXT (see Figure C-3 ).