Microelectronics | IDC DATA CABLES


Once the ISA I/O Interface was completed, I decided to make some custom length data cables that will correctly fit the old InWin IW-Q500 PC case.

I need the following cables.

  • One Floppy Disk Drive cable configured for 3½ 1.44 Mb (A:) and 5¼ 1.2 Mb (B:)
  • Two IDE Hard Disk Drive cables configured as 40-pin interface to 44-pin interface

For some reason I was always attracted by IDC ribbon cables. In my 1990s acception, these cables meant only one thing: high speed data highway. These days, however, serial data transmission cables are used for even faster data transfers than what can be achievable through parallel cables. In fact parallel data transmission technology appears to be obsolete already.

This project is in its final stage.

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Laudatur ab his, culpatur ab illis. This project is provided as-is and is not for commercial purposes. It reflects my experimental work in microcomputer system design and should be treated as such. I release the plans to the public for educational purposes. I did all this on my expense and in my free time. So if you like my work, please consider a donation.

Bill of Materials (BOM)

The following list contains the parts that are required to assemble these IDC data cables.

IdentifierValueQtyNotesMouser Number
X1-FDD, X3-FDD34-pin IDC Connector22.54 mm Wire Housing Pitch617-09185345813
X2-FDD34-pin IDC Card Edge Connector12.54 mm Wire Housing Pitch517-3463-0001
N/ACard Edge Connector Accessory1Polarizing Key517-3439-2
N/A34-conductor Flat Ribbon Cable31.27 mm Conductor Spacing, 28 AWG517-3365/34FT
X1-HDD40-pin IDC Connector22.54 mm Wire Housing Pitch617-09185405813
X2-HDD40-pin IDC Connector22.00 mm Wire Housing Pitch152244-0100-GB
N/A40-conductor Flat Ribbon Cable31.27 mm Conductor Spacing, 28 AWG517-3365/40FT

Construction and Pictures

The 34-pin IDC connectors have an additional plastic part called a strain relieve. I would've liked that the card edge connector (the one that connects to the 5.25" floppy disk drive) was the same color as the 34-pin IDC ones.

Say hello to my little friend. We have a long history crimping IDC cables. So, we meet again!

This twist is mandatory as per floppy disk drive official documentation. Motor enable and control signals are inverted for first floppy disk drive. For the second one, the signals are not inverted.

This small plastic piece is called a polarizing key for standard card edge connectors. In case of the 34-pin 5¼ floppy disk drives, it needs to be mounted immediately after the second pin. Now the cable can only be inserted in one direction.

I have used Kapton tape on the IDC connectors so that my X-Acto knife glides easily without damaging the connector plastic material. The small sharp knife cuts the tiny wires and their insulation like butter.

Assembled floppy disk drive data cable. It looks way better than I imagined.

Copyright © 2004- Alexandru Groza
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