Xerox 4213 manual Null modem, Asynchronous serial signals and pin assignments, Telephone Co

				INTERFACES
	Table 1-6.	Asynchronous serial signals and pin assignments
			Telephone Co.	CCITT
Pin	Signal		designation	designation
1	Protective Ground		AA	101
2	Transmitted Data		BA	103
3	Received Data		BB	104
4	Request to Send		CA	105
5	Clear to Send		CB	106
6	Data Set Ready		CC	107
7	Signal Ground (common		AB	102
	return)
8	Carrier Detect		CF	109
11	Printer Ready		None	None
20	Data Terminal Ready		CD	108

Null modem

A null modem is a device which eliminates both a modem and a telephone line. Figure 1-6 illustrates typical null modem wiring. When the 4213 is used with an asynchronous serial interface connected to a DTE host (such as a PC-compatible), a modem, modem eliminator, or a null modem is required. Figure 1-6 shows null modem wiring.

XEROX 4213 LASER PRINTER PROGRAMMER REFERENCE 1-15