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Posted By: sph Custom cable/pinning question - 11/12/08 08:30 AM
1. Is there an easy way to short conductors in regular UTP cable so that pins 2 & 5 (for example) receive the same signal? I'm looking for something less messy than a splice or soldering. Is there anything similar to shorting bars such as used on rj48 and rj31? And if there is, is there a specialized tool for this?

2. Is there an easy way to do the above, but on 25pair cat3 pairs? For this job, I was thinking of ordering one of these, to start: AMP wear adapter
This thingy opens up to give you access to all 25 pairs. I guess I could figure a way to jump wire from one conductor to another one, or is it a pipe dream.

Thanks!
Posted By: hbiss Re: Custom cable/pinning question - 11/12/08 10:00 AM
What you want is a cross connect field.

-Hal
Posted By: sph Re: Custom cable/pinning question - 11/12/08 01:28 PM
Quote
Originally posted by hbiss:
What you want is a cross connect field.

-Hal
I know, but for a variety of reasons this has to be a custom cable or adapter. The 4-pair is for a serial application. In the 25-pair case, the customer has a 24-port-rj-to-single-amphenol patch panel. Unfortunately the application requires the 25th pair, which is not wired on the panel. I don't want to mess with the customer's panel if I can avoid it. I could use a xconnect in this case, I suppose, but a custom cable would be so much cleaner (and better since it eliminates a cross connection).
Posted By: hbiss Re: Custom cable/pinning question - 11/12/08 01:50 PM
Well, if you could post a schematic for what you want to do maybe I could suggest something. 24 ports of 4 pair is a lot more than a single Amphenol so I have no idea what you are talking about.

-Hal
Posted By: Kyawa Re: Custom cable/pinning question - 11/12/08 03:47 PM
I can make you any assembly you need.
Posted By: sph Re: Custom cable/pinning question - 11/13/08 02:23 PM
OK, here are more specifics. This is about 2 different cables.
First one is for a serial application that is not working properly. The devices connect through 4-pair CM UTP cable with 8P8C rj45-size connectors wired as RS232 serial. The manufacturer of the device suggested shorting 2 of the conductors to fix what they think is a handshake problem. I can splice the wires, no problem. I can also solder them together. But I was wondering if there was a less messy way, like a modular plug with configurable shorting bars or something in that vein. There ARE so-called jumper adapters, such as this one that I could use. That would mean going from RJ45 to DB25 and back - not a pretty sight.

Second question: customer has a Leviton 24-port rackmount voice panel. Connects to devices through 8P2C rj45-size connectors, wired as rj11. Connects to the PBX through a 50P/48C amphenol connector (pair 25/50 in the amphenol is NOT wired). Regular Telco Cat3 25pair patch cable is used. This application requires use of pair 25/50, but several other amphenol pairs are NOT used by the application. I want to jump the 25/50 pair to one of the pairs that are NOT used by the PBX, but ARE wired on the panel, so I can connect the device relevant to the application to a rj45 port. I was wondering if there's a way to this again avoiding splices or soldering either at the patch cable or at the customer's voice panel. As I mentioned above I'm leaning towards using the AMP wear adapter and their insertion/extraction hand tool (put in an order for both) and then do the do at the adapter. But any ideas are welcome.
Posted By: bfdatacom Re: Custom cable/pinning question - 11/13/08 02:48 PM
I wouldn't splice the 4-pair wires, I would fix the handshake problem by jumpering the pins on your RS232 adapter. You don't need to buy a serial adapter, just jumper the appropriate pins on the connector. You just need either male or female pins.
Posted By: Arthur P. Bloom Re: Custom cable/pinning question - 11/13/08 02:49 PM
You are in essence looking to create a break-out box for your 4-pair cable or patch cord. That is the term of art that you are searching for. Breakout boxes are used in many applications to allow you to get access to, and test, individual leads in a cable.

For your first application, use two 8P8C jacks, installed in a 2-port faceplate, screwed to a single-gang box. Plug your patch cords into the two jacks, so that the two jacks are in series with your devices. Be sure to use either 568A or 568B wiring protocol for both jacks. Inside the box, you can run 8 individual leads from jack #1 to jack #2. You can manipulate the leads any way you want, for your needs. You can open, short or cross them, as necessary.

For your second application, you need a Western Electric (made by Amphenol) or equivalent KS-19252 List 1, 2, 3 or 4, "3-way bridging adapter" that will allow three 25-pair cables to merge in one adapter. These adapters are small, about 3" by 3" by 5", and are comprised of three 25-pair Amphenols in parallel. See BSP section 461-200-102 as a reference.

List 1 is CPC, list 2 is PCP, list 3 is PPP and list 4 is CCC, where P stands for plug (male) and C stands for Connector (female).

(As a mnemonic, we also use slang for parts of the human anatomy to refer to the C and P, but since this is a G-rated forum, "the solution is left to the intuitive reader.")

The specific list# that you need depends upon the gender of the mating cables that you are dealing with. You can use these adapters to create a bridged output, into which you can insert a third 25-pair cable, and from it derive the pair(s) you need.

Many of us dinosaurs have 25-pair adapters in stock, from the previous century.
Posted By: hbiss Re: Custom cable/pinning question - 11/13/08 02:53 PM
How many of these are you talking about? I'm assuming one of each instance so maybe Ken would be willing to make something up for you, maybe not.

Your problem with the patch panel is exactly the reason we preach NEVER to use patch panels for voice. ALWAYS use a cross connect field. I know it's not going to help you since I don't think you are willing to smack some sense into the people responsible and change it. But it does illustrate what we are talking about to anyone else foolish enough to consider doing the same thing. It's ALWAYS going to bite you in the ass.

-Hal
Posted By: sph Re: Custom cable/pinning question - 11/14/08 06:07 AM
Thanks for your replies.
Ken, thanks for the offer, I can make the cables myself (need 6 of them), I was just wondering if there was an easy way to go about it. As I said, a field configurable modular plug with shorting bars would be perfect, if it existed.
bfdatacom, your suggestion makes sense, but the connection is UTP/RJ45 all the way through (enviromental sensor to serial-to- ethernet device). After a lot of asking around, I realized the wiring was not the standard EIA/TIA 561: RS232 Over RJ45 but a so-called Yost wiring: Yost serial
The manufacturer of the sensors suggested a null modem cable with partial handshake as in this page: Scroll to partial handshake . I'm trying to do it nice and not go the bulky adapter route. How do you short RJ45 pins in a proper way? It's much harder than I thought.
Arthur, thanks for the info and the humor. I was thinking about the dual jack option myself or maybe a splice box? As for the KS 19252 adapters, they're proving very hard to find! A couple of places I called were more interested in buying them from me. They would work, I'm sure, but I've already ordered the AMP wear adapter as well as this and I'll give it a go.
And then as hbiss suggested there's always the 66 block option with amphenol in/out. That's the easiest, and I agree it would make much more sense to begin with. It never ceases to amaze me when people are duped into going for something that is not only more expensive but also less flexible. It looks good in the rack, I guess.

PS I'm writing this on a new Apple Air notebook at the apple Store here in NYC. Very sleek, I came in here on my way to work looking for a likely post-Christmas purchase (when prices come down a bit). It definitely's got the looks, I'm putting it through paces to see how well it works. Not very cheap compared to Windows notebooks.
Posted By: bfdatacom Re: Custom cable/pinning question - 11/14/08 09:41 AM
I was thinking you were going to use something like this......
https://www.cablestogo.com/product_...681&gclid=CITh7tKb9ZYCFQ89awodaksaZg
Posted By: rustynails Re: Custom cable/pinning question - 11/14/08 10:49 AM
Sph,

I have a few clients using twisted pair for dumb terminals which connect through concentrator hubs and a unix box.

Shorting "leads" is quite common and I always do this within the shell of the 8cond/db25 connector attached to the serial device. You can custom make these per spec in no time at all.

https://www.pccables.com/01915.htm
Posted By: sph Re: Custom cable/pinning question - 12/01/08 03:52 PM
What happened:

The serial cable problem: We used a 110 block to bridge/reroute the individual leads. Then just run short custom patch cables to the serial hub because - just to be a bit safer - we wanted to snip all unused leads when we crimped the patch plugs. Also used termination caps on the C4 blocks which may have been overkill. The good news: the scheme works, even if the tech support of the manufacturer were non-commital about it.
Prior to that, I did try to solder 2 UTP conductors TOGETHER as an experiment and crimp them on a plug, and it's PITA. Then I used 22 AWG UTP and it was much better. Unfortunately there was no 22 size wire installed at the site.
I've posted links to a few serial-related pages. This is my latest fav for all things serial:
web page

This is an excellent resource. That being said, I do hope I don't have to see another serail connectivity problem any time soon.

The amphenol problem: That was easier. Just opened up the AMP wear adapter (covers snap off to reveal the connected pairs) and after some practice, managed to use the AMP extraction/insertion tool to wire pair 25/50 on one side to pair 23/48 on the other. I had to strip a bit of the conductors, as the tool inserts, but does not terminate. Or maybe I wasn't that good at it. Also, I thought the adapter's "sockets" would have gel inside, but no luck. According to AMP's support, some of them do have gel, but there's no way to know beforehand, you got to hit on a lucky batch, I suppose. Another item that thankfully turned out to be wrong was the adapter's wiring: somebody in the office insisted that it was wired as AMP (pairs in sequence as in pair 1 is positions 1/2, pair 2 is positions 3/4 etc). It is actually following the AVAYA (telco) wiring.

Thanks to everyone for your comments and suggestions.
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