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.

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

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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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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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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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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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).

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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.