3Com S27x EIA 232-D Signals Motherboard and SDB, Function/Signal Pin, Function/Signal Name

	Appendix A
	Cables
Overview
Introduction
	The tables in this appendix describe the pinouts for ports on the PathBuilder S24x,
	26x, and 27x switch. Cable pinouts for Ethernet and LAN cables are also provided.

The following table shows EIA 232-D signals with V.24 DIMs on the motherboard and SDB cards.

EIA 232-D Signals (Motherboard and SDB)

Pin		DCE	Function/Signal		Pin		DTE	Function/Signal Name
		Position	Name				Position
1	---------------		Shield/Frame Ground	1		---------------		Shield/Frame Ground
2	<-------------		TXD	2		--------------	>	TXD
3	--------------	>	RXD	3		<-------------		RXD
4	<-------------		RTS	4		-------------	>	RTS
5	--------------	>	CTS	5		<-------------		CTS
6	--------------	>	DSR	6		<-------------		DSR
7	---------------		Signal Ground	7		---------------		Signal Ground
8	--------------	>	DCD	8		<-------------		DCD
14	<-------------		DATA RESTRAINT	14		--------------	>	DATA RESTRAINT
15	--------------	>	TRANSMIT CLOCK or	15		<-------------		TRANSMIT CLOCK
			V.54 Loop 3 *
16	--------------	>	STANDBY	16		<-------------		STANDBY INDICATOR
			INDICATOR
17	--------------	>	RECEIVE CLOCK	17		<-------------		RECEIVE CLOCK
18	<--------------		EXTERNAL RECEIVE	18		--------------	>	EXTERNAL RECEIVE
			CLOCK					CLOCK or V.54 Loop 3 *
20	<-------------		DTR	20		--------------	>	DTR
21	<-------------		V.54 Loop 2	21		--------------	>	V.54 Loop 2
22	<------------	>	RI/TM *	22		<------------		RI
24	<-------------		EXTERNAL	24		--------------	>	EXTERNAL TRANSMIT
			TRANSMIT CLOCK					CLOCK
25	<----------		MAKE BUSY	25		-------------	>	TEST MODE

* Pin assigned double function as follows:

Outputs RI when switch is on. Otherwise, it acts as a TM input signal.

Cables A-1