5++ in 1 Multi-Cable




If you are one of those people who never has the right cable when they need it then this project is for you. Turn one cat5 network cable into the Megatron of cabling by wiring custom adaptors and bridges. This straight through cable can transform into a crossover, serial, serial null-modem, cisco console, vga or vga extension cable by using four adapters, two links and one couple.

This project was originally published in vol 1 of Make (www.makezine.com) on page 96 and i highly reccomend reading it. Easy to follow wiring diagrams make it the perfect reference to read alongside this version. I've added a couple things you wont find in the mag such as vga over ethernet and alternate tecniques for creating the plugs.

Have fun and as always you can get me at jacob@makezine.com

Step 1: Get Parts and Tools

1 Length of Cat5 ethernet cable (complete cable)
1 Length of raw Cat5 cable
2 RJ45 to DB9 FEMALE (serial) converters
alternate: 2 RJ45 to DB9 male AND 2 DB9 female
2 RJ45 to HD15 MALE (monitor) converters
alternate: 2 RJ45 to DB9 male AND 2 HD15 male
1 RJ45 couple
4 RJ45 plugs
1 F-F HD15 gender changer (changes male to female)

Soldering iron and supplies
RJ45 crimping tool
Wire cutters/strippers

If you have no use for a male to male vga cable you can replace one of the male HD15 connectors with a female and you wont need to buy the gender changer.

Step 2: Create the Mini-Crossover

To make a regular straight through ethernet cable into a crossover we will create a mini cable a couple inches long to flip the nessicary wires and add it to the regular cable with the couple. The first thing to do is strip the outer shielding and crimp on the RJ45 plug with the following connections:

RJ45 Pin1: white-orange
RJ45 Pin2: orange
RJ45 Pin3: white-green
RJ45 Pin4: blue
RJ45 Pin5: white-blue
RJ45 Pin6: green
RJ45 Pin7: white-brown
RJ45 Pin8: brown

RJ45 Pin1: white-green
RJ45 Pin2: green
RJ45 Pin3: white-orange
RJ45 Pin4: white-brown
RJ45 Pin5: brown
RJ45 Pin6: orange
RJ45 Pin7: blue
RJ45 Pin8: white-blue

The RJ45 pins are numbered from left to right if you are looking at the bottom (the side without the tab) of the connector with the tip pointing up.

Step 3: Make the Cisco Adapter

This cable is made the way as the crossover with this pin configuration:

RJ45 Pin1: white-orange
RJ45 Pin2: orange
RJ45 Pin3: white-green
RJ45 Pin4: blue
RJ45 Pin5: white-blue
RJ45 Pin6: green
RJ45 Pin7: white-brown
RJ45 Pin8: brown

RJ45 Pin1: white-brown
RJ45 Pin2: brown
RJ45 Pin3: white-green
RJ45 Pin4: green
RJ45 Pin5: orange
RJ45 Pin6: white-orange
RJ45 Pin7: white-blue
RJ45 Pin8: blue

Since it would be hard to tell this cable from the crossover it is nice to use another color cable, I did not have any other colors on hand so mine met Mr. Sharpe.

Step 4: Wire the DB9 Plugs

The two DB9 plugs that i found were male and we need female, so we have to convert them. The first thing to do is open the housing, there should be four clips that hold the two halves together. Once inside the case you can remove the guts of the plug and cut off the plug we wont be using. We can then solder these wires into the proper order:

RJ45 Pin1 (blue): DB9 Pin3
RJ45 Pin2 (orange): DB9 Pin5
RJ45 Pin3 (black): DB9 Pin2
RJ45 Pin4 (red): DB9 Pin7
RJ45 Pin5 (green): DB9 Pin4
RJ45 Pin6 (yellow): DB9 Pin5
RJ45 Pin7 (brown): DB9 Pin8
RJ45 Pin8 (white): DB9 Pin1 and DB9 Pin6

It is best to start by jumping pins 1 and 6 then finishing the top row of the DB9 connector. Once all the wires are connected put everything back in the housing and close it up. Repeat this process exactly for the second DB9 connector.

Step 5: Wire the HD15 Plugs

Open the RJ45 conversion housing and clip off the old connector. Strip the wires and solder them into the new connector according to the following chart:

RJ45 Pin1 (blue): HD15 Pin14
RJ45 Pin2 (orange): HD15 Pin13
RJ45 Pin3 (black): HD15 Pin3
RJ45 Pin4 (red): HD15 Pin7
RJ45 Pin5 (green): HD15 Pin2
RJ45 Pin6 (yellow): HD15 Pin5 HD15 Pin8 and HD15 Pin10
RJ45 Pin7 (brown): HD15 Pin1
RJ45 Pin8 (white): HD15 Pin6

Since pins on HD15 connectors are pretty cramped it is easiest to solder the middle row first then move to the two outside rows. Repeat this for the other HD connector and then your finished with construction!

Step 6: Use the Cable

Using the multi-cable isnt quite as daunting as it may initially seem here are the connections for the different configurations

Straight through ethernet:
Cat5 to Cat5

Crossover ethernet:
Cat5 to Cat5 - Couple - Crossover Mini-Cable

Serial cable:
DB9 - Cat5 to Cat5 - DB9

Null modem serial cable:
DB9 - Cat5 to Cat5 - Couple - Crossover Mini-Cable - DB9

Cisco console cable:
DB9 - Cat5 to Cat5 - Couple - Cisco Mini-Cable

VGA cable:
HD15 - Cat5 to Cat5 - HD15

VGA monitor cable
Gender changer - HD15 - Cat5 to Cat5 - HD15

Congratulations on your new cable creation! This general method can be used to emulate all types of interesting cables (that use eight or less conductors) so dont be limited to just the connectors in this how-to. Using google and a soldering iron you can make almost any cable you'll ever need!



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      40 Discussions


      5 years ago on Step 3

      this is a big help with what I was planning to do, except I don't understand why you used two rj45 jacks. my plan is to use a rj45 jack, cable and keystone jack.

      I was going to post saying that the blue and brown wires should not crossover but then I realized this is for a gigabyte connection. If it is for a gigabyte connection I would make a full cable for it and not use Cat5 I would go with Cat6 or if the connection needs to be at a gig and is highly impotent Cat7(yes there is
      Cat7 and it is a pain).

      no lol im not pretty young . im like your age i turn 16 in ....less than a month so ya im a 1992'r lol. but no every computer i EVER had i never had anything run on serial.. (prehistoric pc w like 500mb'ish hdd, 95 bell pc, mac g2, mac, mac g4, 98 dell, 2000xp, etc. lol but now im using my dream computer :DDDDD ...just amazing lol. and still havent came acrost a serial input device, even know the zillians of things iv used still LOL.

      I still use RS232 (Serial). Softmodding satellite boxes ftw. I'm seriously surprised you've never used serial, I've owned tons of serial devices over the years.


      Reply 11 years ago on Introduction

      The only serial devices I have ever owned are a mouse, a scanner, and my picaxe cable. What mods can yo actually do to a satellite box then? That sounds really interesting.


      Reply 11 years ago on Introduction

      serial is incredibly useful, though most consumer devices dont use it any more. most modern flat panel LCD/Plasma TV screens have a control/service port on the back where you can control the screen from a comp, linux MCE uses it to trun the screen on/change inputs/etc. i use it for homebrew stuff (unable to afford large tv rofl) such as my pic programmer, but also on network stuff ive picked up second hand or when the screen dies on my linux box and i use the serial port with a simple console thing to get access again

      Just about any I/O device was made at one time to use RS232 serial. Mice especially, but also printers, scanners, Disney sound source I think used it, UPS, external hard drives and CD-ROMs, etc. PS2 keyboards and mice still use a type of serial interface though I believe it is different from actual RS232. I've never done low level programming for those though so it might be the same or it might not, but it's definitely some type of serial. I still use serial from time to time for shell access to computers running Linux and to shell into my TiVo which also runs a type of Linux. Mostly though I use XbaseT to access those but serial is still handy for when the network decides it's not going to work. Actually network is a type of serial connection but it uses different protocols from RS232. Good Cisco routers will have a serial port for changing settings. Also USB and FireWire/IEEE1394 is a type of serial connection.


      Reply 8 years ago on Introduction

      Not even 'similar protocols'; the difference between serial, PS/2 and USB is like the difference between pineapple, cabbage and pork.
      USB uses differential signaling, serial and ps/2 do not.
      Serial is officially +/- 12v (up to +/-15v) though many OEMs cheat.
      PS/2 is 5v, USB is 3.3V
      PS/2 is a synchronous protocol, whereas serial and USB are asynchronous.
      USB has built in support for multiple, distinct devices; serial and PS/2 know only of the two ends of the cable.
      There are ways of operating between some combinations of these, but it requires significant hardware and software to do it. The combinations that I know of are:
      USB ->Serial
      PS/2->Serial (though this is just a pinout adapter. the hardware switches to a different mode to use this)
      PS/2->USB (another pinout adapter, and just like the above, the hardware must be able to make the distinction, or it won't work)

      Mostly routers/switches now-a-days. Time clocks. Dialup modems (yes, they are still used for maintenance purposes on some equipment). Lots of scientific/telecom equipment. UPSes. It's still in use enough that Dell decided to forego PS2 ports on some of the servers I have, but they still have a serial port! Someone else mentioned CDRom & external HDs, but I doubt that was ever the case (too slow). The Disney Sound Source used the Parallell port, I had one in the 90's. Do you have a Linksys router? They have a serial connection (it's on the PCB, but not wired up to reduce costs).