TIU to AIU cable

Isn't it a simple phone cord?  

You can definitely make them longer.  Mine is 6' long and I think someone on the forum has gone further.  Can't recall if it is any type of standard phone cord but yes they can be extended.  I'm sure someone can chime in on the pin out.

Isn't it a simple phone cord?  

No, it is not. The cable is a standard 6-conductor phone cable.

While there is a physical limit as to how far the TIU can push a very low voltage signal, I have a series of 5 AIUs connected to a TIU with one of the cables being 25 feet. Although I have no issues with my setup, all of the 4 other cables are of standard length. I cannot say if a longer end-to-end run will also work well.

Barry, you probably know this outright.  In the AIU, is the output signal buffered or is it just daisy-chained from the input signal?

John,

In the AIU, is the output signal buffered or is it just daisy-chained from the input signal?

The latter, I believe.

Barry,

I assume I can get a 6 conductor cable at Radio Shack?  Also I'd like to post some pictures, but I'm having trouble. Is there something I need to do?

Thanks,

Don Keence

You can use a standard 6 conductor phone cord for the AIU, I just took one out for one of my multi-line phones and swapped it for the MTH one, worked fine.

You can use a standard 6 conductor phone cord for the AIU,

There must be an echo in here...

Don,

I assume I can get a 6 conductor cable at Radio Shack?

Maybe,  maybe not in the store. You should be able  to get one on their web site, however, it won't be your most economical option.

Also I'd like to post some pictures, but I'm having trouble. Is there something I need to do?

Start by making a new post and clicking on "Add Attachments" at the bottom of the new post window.

Thanks for the info. I couldn't post pictures till I downloaded Adobe flash. Here are a few of my trestle. My wonderful wife is in the one pic to give it perspective ( she's 5'4" ) plus she puts up with my train mania.The trestle is made up of 6" tall sections stacked up to 38" at it's tallest point. Just like a real trestle.

Don Keence

That is a LOT of Popsicle sticks!   What a great looking trestle, very imposing!

Thank you. It was my first & last!LOL

I run a bank of AIU's 35 feet from the TIU.  Gerry Morlitz is about 50 feet out to his last AIU. 

Marty, That's great. I'm only going 10'-12'.I'm still looking for a source to buy a cable.

Thanks,

Don Keence

What was wrong with all the sites I posted?

Gunrunnerjohn,

 Sorry I'm not very computer savvy. After I posted my reply, my daughter came over and showed me those were links to sites. I've since ordered a cord. I'll let you know how it works when I get my switches hooked up.

Thanks,

Don Keence 

Sorry Don, I didn't realize you didn't know they were links.

Hi guys,

The AIU cable is NOT the same as a telephone wall cable.  For starters, the AIU cable has 6 conductors (wires) (RJ12 or RJ25).  Many off-the-shelf telephone cables only have 2 (RJ11) or 4 (RJ13 or RJ14) conductors.  Most of the time when you buy a telephone the cord that comes with it will only have four wires for two incoming lines.  The cables that gunrunnerjohn linked to above all have 6 conductors, however, they are "straight through" cables.  That means when you hold the plastic end crimps side by side the colored wires will be in the same order from left to right.

The AIU uses a "crossover" cable.  When you hold the crimps side by side the colors are in opposite order.

If you use a straight through cable to connect any generation TIU to any AIU, the AIU will not function and you will usually get a "CHECK TRACK" error message when attempting to use a switch or accessory that was previously programmed.  If you use a straight through cable to connect any TIU to early production AIU's (2002-2003 - most have a Protosound 2 logo in place of the DCS logo) YOU WILL DAMAGE THE AIU.  The AIU's can be repaired for a reasonable cost, but a little knowledge can save you some money and a headache.

You can easily make custom length AIU cables by purchasing a crimping tool like THIS.

The maximum length of the cables depends on which AIU terminals you are using.  The cable carriers two different things - DCS commands to control the relays AND the electrical current to energize the relay coils.  If you only use the switch terminals you can take the total AIU cable length well over 100 feet with reliable operation.  That's because only one relay coil can ever be energized at one time.  When you start using the accessory terminals you can have many coils energized simultaneously causing greater voltage drop over a long wire run.  If you are using even just two accessories you are tripling the current draw through the AIU cable.  If you use a lot of accessories it's best to stay under 25 feet of total length between all the AIU's in a given daisy chain.

I just took out the short cable I used, it is a flat cable that is crimped just like the TIU->AIU cable.  You're right Dave, they do reverse the pins, I guess that's the phone standard!

Now I'm trying to figure out why you'd wire them any other way...

It appears that this is actually the compatible cable: Phone cable, RJ12 (6P6C), Reverse - 7ft for Voice

Sorry for the mixup.

I guess that's the phone standard!

No, it's NOT the telephone standard.  The telephone standard is "straight through" (first photo above) which won't work with an AIU.  That's why it's easy to get in trouble if you go down to Radio Shack and buy a regular phone cable with 6 conductors.  At best the cable won't work and if you have older DCS hardware you can do damage.

John, I know you said earlier that you got the cable you're using from Radio Shack, but it's not a standard wall cable.  One of three things must have happened.  Either it was a fluke that was crimped wrong at the factory, a cable that was modified, or you happened to grab a crossover cable (which I don't think they stock in-stores).

It was a cable for a three line phone, and it came that way with the phone from Radio Shack years ago.  I had it in my parts box.  It's a short jumper cable about 8" long that has all six wires, it went from the wall plate to the phone.  The phones died long ago and were pitched, but I have the cable (and another like it) in my cable box.  It never occurred to me that it was "special", I held it up to the AIU cable and decided it was wired the same and tried it.  FWIW, a longer (about 6 feet) three line phone cable also worked with the three line phone and the TIU, it's wired the same way.  It also came with the phones.

Thanks for keeping us honest, we do have to be careful out there.

FWIW, the last time I bought an AIU replacement cable from Radio Shack it was a 25 foot long crossover cable. That was several years ago and it's still in service today.

I guess I had crossover cables all this time and didn't know it.

FWIW, I just checked the only three line phone I have left, a Panasonic, and it's also connected with the same crossover cable.

Right you are Ted, done!

Thank you.