External links, 'Complete pinouts guide to Parallel-Serial Port, Network'


An Incomplete Guide to Parallel and Serial Port Cable Pinouts

Everything for DCC (Direct Cable Connection of Win95, Normal and Null Modem Cables, etc.

This guide is compiled/collected/prepared/experimented by Mahendra from India (My Fabulous Personal Web Page)
Mail me at mahendra@geocities.com
Please visit another great Web-Page on INDIA designed by me explaining everything about INDIA.
DOWNLOAD this single page information in HTML format by clicking on PINOUT.HTML, but never forget me.

INDEX of Chapters
1. Preface
2. IBM Basic concepts of Computer Cabling.
3. IBM DB-25 and DB-9 diagrams.
4. IBM DB-25 and DB-9 numbering scheme.
5. IBM Parallel Port Laplink Cable Pinout.
6. IBM Null-Modem pinouts. (DB-25 to DB-25), (DB-9 to DB-9) and (DB-25 to DB-9).
7. IBM Normal Modem pinouts.(Modem Cable) (DB-25 to DB-25) and (DB-25 to DB-9).
8. IBM Wire name for each pin number.
9. Other Cables & Pinout Related Links
10. WARNING


1. PREFACE

Here are several diagrams and tables explaining parallel port, serial port and null-modem configurations, which are mostly available on Internet. I was forced to provide this information on the Internet by myself when my search began for getting Laplink Cable or Null Modem Cable to transfer data from one Win95 PC to another Win95 PC in Sept-97. I bought the laplink cable in the market and that served my purpose as I successfully transferred data from "HOST" to "GUEST" computer with Laplink. But also I was bit worried with the cost of LAPLINK cables available in the market as I purchased it at at least thrice the cost of its material cost. Let's discuss this in Indian Rupees. I purchased Laplink cable at Rs.120/- in the market. But the material cost I calculated was only Rs.50/- if we prepare this at home if you have a logically working BRAIN and a little bit knowledge of soldering wires, which most of us do while repairing toys or portable radios. So I did opened the D-25 Female pins of my Laplink cable and studied the colour combinations of wires and prepared the following PINOUT Chart for those who want to make LAPLINK Cable at home. (THIS IS JUST AN INFO PAGE, BUT PLEASE USE THIS INFO AT YOUR OWN RISK.)

The other information available on this page are the collection of information available on Internet elsewhere and also from someone from geocities whose name I forgot. But its somebody called "Acclaim@geocities.com". Here we go with the duscussion....

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2. BASIC CONCEPTS OF COMPUTER CABLING

A PARALLEL port can consist of only 25 pin port adapter called a DB-25 and a serial port can consist of either a 25 pin port adapter called a DB-25 or 9 pin adapter called a DB-9 port adapter. Whether the port is a 9 pin or 25 pin it can accomplish all of the same tasks that serial port communications have been designed for.

Each adapter can be a male type connector with pins or a female type adapter with tiny holes.
Generally a PRINTER port (called LPT1) on the back of a computer is female type adapter and we need to use MALE DB-25 pin cable on it for PRINTER connection or for parrallel LAPLINK cable.

And a COM port on the back of a computer is male for the serial ports but it may not necessarily be. Below are diagrams of a DB-25 and DB-9.

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3. IBM DB-25 and DB-9 diagrams.

(Each diagram on this page is the view you see when you look into the end of the cable from the outside of the cable.)

The "o" characters represent holes, the "." characters represent pins.
A DB-25 looks like this...

Diagram #1
Female:                        Male:
_____________________________  _____________________________
\ o o o o o o o o o o o o o /  \ . . . . . . . . . . . . . /
 \ o o o o o o o o o o o o /    \ . . . . . . . . . . . . /
  -------------------------      -------------------------


And a DB-9 is like this...

Diagram #2
Female:        Male:
_____________  _____________
\ o o o o o /  \ . . . . . /
 \ o o o o /    \ . . . . /
  ---------      ---------

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4. IBM DB-25 and DB-9 numbering scheme. (Pin numbers)

Each pin has a number assigned to it. When connecting null modem, for example, it is important to know these numbers in order to select the correct cables, or when making your own cables.

DB-25 Connector
Chart #1 (Female)
  13              <------- 1 
 _____________________________
 \ o o o o o o o o o o o o o /  
  \ o o o o o o o o o o o o /
   -------------------------
    25             <----- 14 
Chart #2 (Male)
  1 ------->              13      
 _____________________________
 \ . . . . . . . . . . . . . /
  \ . . . . . . . . . . . . /
   -------------------------
   14 ----->             25 
DB-9 Connector
Chart #3 (Female)
   5 4 3 2 1
 _____________
 \ o o o o o /
  \ o o o o /
   ---------
    9 8 7 6    
Chart #4 (Male)
   1 2 3 4 5
 _____________
 \ . . . . . /
  \ . . . . /
   ---------
    6 7 8 9    

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5. Parallel Port Laplink Cable Pinout

Laplink cable is used to link two PCs with MSDOS 6.0 or later, very effectievly by using INTERSVR.EXE (on Host) and INTERLNK.EXE (on GUEST) PCs.

Laplink cable is also successfully used by me to link two PCs with WIN95 and Direct Cable Connection program with common protocol as "NETBEUI" on both Computer's Network Section of Control Panel. Rest is explained in HELP and Troubleshooting Section of WIN95 itself.

Parralel port Laplink cable is always faster than Serial port Cable because of more numbers of cores of wires used in Parallel port cable (25 pin) than Serial port Cable (9 pins).

If you are seeking to buy a Parralel port Laplink cable, or trying to make your own cable, you should know what pins need to be switched in order to make it. Below is a chart of what pins go to what on the other end. Only 18 pins are used in a Laplink Cable, therefore I will only show those eighteen here.

To make this cable we need
1. TWO numbers of DB-25 Female Sockets.
2. Shielded Cable with 18 cores (lines of wires).

Chart#5
DCC Parallel Laplink Cable Pinouts.
Female DB-25 ==>> Female DB-25
1 Both Not used
2 to 15
3 to 13
4 to 12
5 to 10
6 to 11
7 Both Not used
8 Both Not used
9 Both Not used
10 to 5
11 to 6
12 to 4
13 to 3
14 Both Not used
15 to 2
16 Both Not used
17 to 19
18 to 18
19 to 17
20 Both Not used
21 to 21
22 to 22
23 to 23
24 Both Not used
25 to 25
Pinbody* to Pinbody
* = In my cable one wire was attached to the metal body of the Female pins on both sides. Total 18 wired cable is necessary for this cable including one wire for Body of the pin too.

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6. IBM Null-Modem pinouts. (DB-25 to DB-25), (DB-9 to DB-9) and (DB-25 to DB-9).

For making Null modem cable following is a chart of pinout. Only 8 pins are used in a null modem, though there are 25 pins on DB-25 socket. You need 8 or 9-wired cable with two DB-25-Female pin socket or DB-9-Female pin socket or one of both.

IMPORTANT : Both pin sockets must be of FEMALE type. This may not be applicable on some machines, so please check your serial ports of both the machines as there must be MALE pins at back of your both computers.

Chart #6
Chart #7
Chart #8
Null-Modem Pinouts
DB-25 to DB-25
2 to 3
3 to 2
4 to 5
5 to 4
6 and 8 to 20
7 to 7
20 to 6 and 8
Null-Modem Pinouts
DB-9-Male to DB-9
1 and 6 to 4
2 to 3
3 to 2
4 to 1 and 6
5 to 5
7 to 8
8 to 7
Null-Modem Pinouts
DB-25 to DB-9
2 to 2
3 to 3
4 to 8
5 to 7
6 and 8 to 4
7 to 5
20 to 6 and 1

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7. IBM Normal-Modem Cable pinouts. (DB-25 to DB-25) and (DB-25 to DB-9).

IMPORTANT : Both pin sockets must be of DIFFERNT type. This means that for modem-side of cable we need to use MALE type of DB-25 pin. And on CPU side of cable we need to use FEMALE type of DB-25 or DB-9 pin.

Chart #9
Chart #10
Normal-Modem Pinouts
DB-25 to DB-25
2 to 2
3 to 3
4 to 4
5 to 5
6 to 6
7 to 7
8 to 8
20 to 20
22 to 22
PinBody* to Pinbody*
Normal-Modem Pinouts
DB-25 to DB-9
2 to 3
3 to 2
4 to 7
5 to 8
6 to 6
7 to 5
8 to 1
20 to 4
22 to 9
PinBody* to Pinbody*
* Pinbody is OPTIONAL. We easily get cable with 9-wires in it, but not 10 then Pinbody can be attached with shielded wire. The one which I examined from a reputed company was having body of pins connected with shileded wire (let's assume earthing line.)

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8. Wire name for each pin number for Serial Cable Connect.

For above all connections we may use following chart for transmission of Data.
Chart#11
Pin assignments
DB-25
2 Transmit Data
3 Receive Data
4 Request to send
5 Clear to send
6 Data Set Ready
7 Signal Ground
8 Data Carrier Detect
20 Data Terminal Ready
22 Ring Indicator
Chart#12
Pin Assignments
DB-9
1 Data Carrier Detect
2 Receive Data
3 Transmit Data
4 Data Terminal Ready
5 Signal Ground
6 Data Set Ready
7 Request to Send
8 Clear to Send
9 Ring Indicator
IMP. NOTE : In DB-25 serial cable following numbered pins are NOT USED. They are 1, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 23, 24 and 25.

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9. Other Links

Apple Mac users guide on Modem Pinouts by RADICAL Systems

Date: wed, 24 Sep 1997 19:51:38 +0100 From: "Jesse Eissens" (jeissens@bigfoot.com)
To: (mahendra@geocities.com) CONTENT : Whould you happen to have the pinout for a 15 pin monitor connector? I have a Compaq and I can't use the volume control on my monitor with my new Stealth 3D card. The volume is controled by the mother board from the monitor to the sound card. I'd like to make a patch cable to fix this problem. I can't seem to get the answer I want from Compaq.

The user himself finds the solution on http://www.interlog.com/~gscott/t-DB15VGA.html


10. WARNING

WARNING : THESE PINOUTS ARE OF THOSE CABLES WHICH I USED SUCCESSFULLY, THEN OPENED AND EXAMINED BY ME FOR YOU. BUT PLEASE USE THIS INFO AT YOUR OWN RISK AND DON'T HOLD RESPONSIBLE TO ME IF YOU MESS IT UP. NOBODY IS PERFECT SO NEITHER I.

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For further requests, changes, questions, corrections, mail me at mahendra@geocities.com. you can ask for changes and queries by specifying Chapter Numbers and Diagram Numbers. Thanks for visiting.

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