[net.micro] IBM PC AT serial connector pinout

phil@amdcad.UUCP (Phil Ngai) (05/10/85)

I was surprised to find the serial connector is a 9 pin guy. I can't
seem to find the pinout in any of my manuals, does anyone know it?
-- 
 I speak for myself and no one else.

 Phil Ngai (408) 749-5720
 UUCP: {ucbvax,decwrl,ihnp4,allegra}!amdcad!phil
 ARPA: amdcad!phil@decwrl.ARPA

kevinp@mmintl.UUCP (Kevin Piette) (05/15/85)

In response to the recent inquiries concerning the IBM PC AT
Serial/Parallel Adapter I have posted the following:

The IBM PC AT Serial/Parallel Adapter has a 9-pin D shell type
connector which is configured as follows:

       Pin	Signal Name (DCE)     RS-232C Pin (DCE)
      -----    --------------------  -------------------
	1	Carrier Detect		 8 (CD)
	2	Received Data		 3 (RD)
	3	Transmitted Date	 2 (TD)
	4	Data Terminal Ready	20 (DTR)
	5	Signal Ground		 7 (SG)
	6	Data Set Ready		 6 (DSR)
	7	Request To Send		 4 (RTS)
	8	Clear To Send		 5 (CTS)
	9	Ring Indicate		22 (RI)

The above is for attachment to Data Communications Equipment such as a
modem.  To attach to another terminal (DTE) device the following signal
lines must be changed:

       Pin	Signal Name (DCE)     RS-232C Pin (DTE)
      -----    --------------------  -------------------
	2	Recieved Data		 2 (TD)    (RD & TD Swapped)
	3	Transmitted Data	 3 (RD)
	4	Data Terminal Ready	 6 (DSR)   (DTR & DSR Swapped)
	6	Data Set Ready		20 (DTR)
      / 7	Request To Send		 4 (CTS) \ (Pins jumpered together at
      \ 8	Clear To Send		 5 (RTS) / each end only in pairs. Pin
						   7 to 8, 4 to 5. Not needed
						   for Full-Duplex operation.)

This information may be obtained from the IBM Technical Reference,
Options and Adapters Mannual, Volume 2 after installing update pages
which are actually provided in the Technical Reference, Personal
Computer AT Mannual.  This means you need the AT tech ref to get the
specification if you haven't already obtained one.

Note:   I agree that IBM makes it difficult to obtain technical info.
	I would explain, but this is the wrong place for that flame.

-- 
Kevin Piette					Phone: (203) 522-2116
Multimate International Corporation, Research & Development
UUCP: ...!seismo!cmcl2!philabs!pwa-b!mmintl!kevinp