RAD Data comm ASM-20 - Manual (Page 62)

Appendix C IR-X.21B Interface Module ASM-20 Installation and Operation Manual
C-4 INT/RCV Mode
Transmit Data
DB
Connector
FIFO
Buffer
IR-X.21
MODEM (EXT)
TD
TC
RD
RC
from DTE
(2,9)
External timing from DTE
(7,14)
Receive Data to DTE
(4,11)
FIFO
Buffer
Signal Timing
(6,13)
Figure C-4 EXT Mode Timing Block
C.5 INT/RCV Mode
This mode is used in applications where the IR-X.21B 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 two
16-bit FIFO’s buffers to compensate for the phase delay introduced by the X.21
device.
Figure C-5 illustrates the buffers 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 ).
MODEM (INT or RCV)
Transmit Data
DB
Connector
FIFO
Buffer
IR-X.21
TD
TC
RD
RC
from DTE
(2,9)
Receive Data to DTE
(4,11)
FIFO
Buffer
Signal Timing
(6,13)
Figure C-5 INT/RCV Mode Timing Block