3Com 3C16985B, 3C16988A Null Modem Cable, PC-AT Serial Cable, Pin to RS-232 25-pin, Pin to 9-pin

B PIN-OUTS

Null Modem Cable	9-pin to RS-232 25-pin
	Switch 3300 XM, SM, TM, MM	PC/Terminal
	Cable connector: 9-pin female	Cable connector: 25-pin male/female

Screen Shell

TxD 3

RxD 2

Ground 5

RTS 7

CTS 8

DSR 6

DCD 1

DTR 4

1 Screen

3 RxD

2 TxD

7 Ground

4 RTS

20 DTR

5CTS

6DSR

8DCD

only required if screen

always required

required for handshake

PC-AT Serial Cable	9-pin to 9-pin
	Switch 3300 XM, SM, TM, MM		PC-AT Serial Port
	Cable connector: 9-pin female		Cable connector: 9-pin female
	Screen				Screen	only required if screen
		Shell		Shell
	DTR	4		1	DCD
	TxD	3		2	RxD		always required
	RxD	2		3	TxD
	CTS	8		4	DTR		required for handshake
	Ground	5		5	Ground		always required
	DSR	6		6	DSR
	RTS	7		7	RTS		required for handshake
	DCD	1		8	CTS