RAD Data comm ASMi-31 - Manual (Page 56)

Appendix C. X.21 Interface Module ASMi-31 Installation and Operation Manual
C-4 INT/RCV Mode
IR-X.21B
MODEM DTE
TXD TXD
ETC
ETC
RXC
RXD RXD
Signal Timing
(2, 9)
(7, 14)
(4, 11)
(6, 13)
FIFO
Buffer
Rx
Figure C-4 EXT Mode Timing Block
C.4 INT/RCV Mode
This mode is used in applications where the IR-X.21 side uses the clock
signal from the modem link. This mode is used mainly when the attached
equipment has an IR-X.21 interface, but no ability to produce clock signals.
The module has a 16-bit FIFO buffer to compensate for the phase delay
introduced by the X.21 device. Figure C-5 illustrates the buffer connection
and the required application setup. When the modem's clock mode is INT
or RCV, the JP2 jumper must be set to INT/RCV (see Figure C-3).
IR-X.21B
MODEM DTE
TXD TXD
TXC
RXC
RXD RXD
Signal Timing
(2, 9)
(4, 11)
(6, 13)
FIFO
Buffer
Rx
Figure C-5 INT/RCV Mode Timing Block
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