RAD Data comm ASM-20 operation manual Figure C-4 EXT Mode Timing Block

Appendix C. IR- X.21B Interface Module ASM-20Installation and Operation Manual

	MODEM (EXT)
	IR-X.21
TD		Transmit Data from DTE
		(Jumpers 2,9)
TC		External Timing from DTE
		(Jumpers 6,13)
R D	FIF O	Receive Data to DTE
R C	Buffer	(Jumpers 4,11)
		DB Connector

Figure C-4 EXT Mode Timing Block

C.6 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 a 16-bit FIFO buffer to compensate for the phase delay introduced by the X.21 device. Figure C-5illustrates 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).

MODEM (INT or RCV)

	IR-X.21
R C	FIFO	Receive Data to DTE
R D	Buffer	(Jumpers 4,11)
TC		Signal Timing to DTE
		(Jumpers 6,13)
TD		Transmit Data from DTE
		(Jumpers 2,9)

DB Connector

Figure C-5 INT/RCV Mode Timing Block

C-4 INT/RCV Mode