Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!srhqla!demott!kdq
From: kdq@demott.COM (Kevin D. Quitt)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: Re: Wiring for null modem cable
Message-ID: <648@demott.COM>
Date: 2 Oct 90 21:56:20 GMT
References: <='Q%5!=@rpi.edu>
Reply-To: kdq@demott.COM (Kevin D. Quitt)
Organization: DeMott Electronics Co., Van Nuys CA
Lines: 47

In article <='Q%5!=@rpi.edu> hydrox@itsgw.rpi.edu (Michael A. Hendrix) writes:
>Can anyone supply me the wiring pattern for a null modem cable with a DB25
>connector on one end and a DB9 on the other end?  I need to move some stuff
>from my 286 to my laptop and need to wire a cable up for this....any help
>would be greatly appreciated.

DB9	RS232				DB25	RS232
Pin	Signal				Pin	Signal
 1	CD	Carrier Detect		 1	CGnd	Case Ground
 2	RxD	Received Data		 2	TxD
 3	TxD	Transmitted Data	 3	RxD
 4	DTR	Data Terminal Ready	 4	RTS
 5	SGnd	Signal Ground		 5	CTS
 6	DSR	Data Set Ready		 6	DSR
 7	RTS	Request to Send		 7	SGnd
 8	CTS	Clear To Send		 8	CD
 9	RI	Ring Indicator		9-19	Not usually used
					20	DTR
					21-25	Not usually used

			  RS232C Null-Modem Cable

		DB9	DB25			DB25	DB9
		Pin	Pin			Pin	Pin
		 1	 8	 CD	DTR	20	 4
		 2	 3	 RxD	TxD	 2	 3
		 3	 2	 TxD	RxD	 3	 2
		 4	20	 DTR	DSR	 6	 6
		 4	20	 DTR	CD	 8	 1
		 5	 7	 SGnd	SGnd	 7	 5
		 6	 6	 DSR	DTR	20	 4
		 7	 4	 RTS	CTS	 5	 8
		 8	 5	 CTS	RTS	 4	 7


		1-6	6-8			6-8	1-6	<- Jumpers

Note:	If for some reason, you cannot jumper DSR to CD, connect
	DSR to the opposite DTR, and connect CD straight across
	(if possible).
-- 
 _
Kevin D. Quitt         demott!kdq   kdq@demott.com
DeMott Electronics Co. 14707 Keswick St.   Van Nuys, CA 91405-1266
VOICE (818) 988-4975   FAX (818) 997-1190  MODEM (818) 997-4496 PEP last

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