Telco Patch Panels and Polarity Problems

[TelNetSystems]

I have a Partner ACS system installed with patch panels on a relay rack instead of a standard wiring block cross-connect field. However, I have had a hard time keeping my polarity consistent using patch cords instead of cross-connect wire.

Here is my rack system:

24 Port 6P4C - Phone Lines : Telco Demark
12 Port 6P4C - Phone lines : Partner ACS
48 Port 6P4C - Extensions : Partner ACS
96 Port 8P8C - Wallplates : 1st RJ-45
96 Port 8P8C - Wallplates : 2nd RJ-45
96 Port 8P8C - Wallplates : 3rd RJ-45
96 Port 8P8C - Wallplates : 4th RJ-45
24 Port 8P8C - Lan Switch 1
24 Port 8P8C - Lan Switch 2
APC RackMount UPS

All jacks are wired straight-through with standard USOC & T568A wiring. When I use standard line cords to patch telephone lines to the Partner ACS and wall jacks, the Partner has correct polarity and the wall jacks have reverse polarity. Straight-through line cords create reverse polarity at the Partner ACS and correct polarity at the wall plates. This drives me nuts.

The best alternative I see is to reverse wire the plugs for the telephone lines at the Partner ACS and use all straight-through patch cables. In that case, it would probably be best to replace the 6P4C panels with 8P8C panels and use RJ45 patch cords for everything. That would elimiate the need for special patch cables and prevent mixups between straight-through telephone line cords and standard reverse wired ones.

Am I missing a better solution? How does everyone else handle this oddity?

 

[daronwilson]

That is certainly a very flexible installation, normally we would not provide so much flexibility for the customer. Mainly because some things rarely need to be changed (like the CO lines from the telco into the key system) and if there are many options for someone in the closet, there is more chance of them putting the wrong patch together and generating a service call.

I agree with your idea, what seems to be the solid to me would be to make your Key System patch panel an 8P8C patch panel and use regular patch cords for all. Normally in this type of installation I would not use a patch panel for the KSU, since this particular KSU has 8P8C jacks on it already for extensions. The few times we've provided a complete patch panel system like this for the customer though, only one was an ACS and I believe we ended up with stranded patch cables from the ACS to the front of the rack, each one labeled with the KSU extension number and those plugged into the field wiring.

Many ways to solve it I'm sure, but you are on the right track.


It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[DToolsDesigner]

When I install telco patch panels I always use either 8P4C or 8P2C panels and use a regular data straight thru patch cord to cross connect to my horizontal cables. Then use 25 pairs cables and connectors on the back of the telco panel from the PBX or KSU. Use Cat 5 patch panels for all my horizontal cables, so all horizontals whether voice or data are terminated the same way. This way all patch cords in the TR are 8P8C.

Then use typical line set cords at the workstation. This also allows for very easy splitting of the pairs for modems and multiple phone sets at the workstation using adapters outside the wall plates and on the patch panels so I don't violate the standards.

You always want to terminate all 4 pairs so you should never have to go back and swap pairs around or split them on the horizontal cable. All pair splitting should be done with adapters plugged into either the workstation for multiple desk sets, or at the patch panel to supply both analog for modems and digital for phones to the workstation.

Another advantage of terminating cables this way, if I ever need to make a voice line a data line, or visa versa it is a simple matter of moving a patch cord, no termination involved, and with proper documentation I can walk the onsite IT personnel through it on the phone. My clients love it because it doesn’t cost them a service call to make simple changes.

On not so large jobs, an added bonus the additional patch panels help fill a 7 foot rack so it doesn’t look so bare.

 

[DToolsDesigner]

I am curious, I don't see any cable management hardware listed. Do you use any?

 

[TelNetSystems]

>> That is certainly a very flexible installation,
>> normally we would not provide so much flexibility
>> for the customer. Mainly because some things rarely
>> need to be changed (like the CO lines from the telco
>> into the key system) and if there are many options
>> for someone in the closet, there is more chance of them
>> putting the wrong patch together and generating
>> a service call.

Hmm... I started the patch panel for incoming telco lines becasue people always seem to have at least a fax line or two, a DSL line, and a shared modem line or two in addition to their pool lines. Using a patch panel and daisy chaining the shared modem lines across several ports made it easy to handle moves/adds/changes for the fax and modem lines. If I eliminated that patch panel and the ones leading to and from the phone switch, I would have to punch the lines down on a block in the same fashion, punch one end of a cable down on the block, and put a modular plug on the other end to feed the phone switch or a wallplate port on the patch panels. Would that be a stranded cable punched down on a 66/110 block, or would that be a solid cable used as a patch cord? I was under the impression that both those scenarios were undesireable.

Also, how does this affect installation and maintenance time versus the cost of the panels? If I don't do patch panels, then as I put up the punch down blocks, punch down all the wires on the blocks, cross-connect everything with cross-connect wire, and crimp modular plugs onto cables to interface to the equipment, I find myself wondering why I thought it was such a good idea to save the relatively minor cost of a patch panel and some cords which could simply be screwed in place, punched down, and jumpered. For those of you who do this frequently, do you find a labor savings when installing on patch panels? Isn't it also easier to maintain when you can walk in, look at the equipment rack, and immediately understand exactly how everything is organized and connected? Perhaps those of you who do this every day can look at a cross-connect field and immediately tell how it is set up. Me... I usually have to do a little bit of tracing and toning before I get the picture of how it was set up by the prior tech and where everything is going.

 

[TelNetSystems]

>> I am curious, I don't see any cable management hardware
>> listed. Do you use any?

I didn't at first, but now I do... what a mess! I now have cable management rings down both sides of the rack and a cable management panel between each patch panel. I left that out because I was afraid of adding so much info that people just quit reading .

 

[DToolsDesigner]

Frankly, I never use blocks anymore. I either do patch panels, for the reasons stated above in my last post, or I won't do the job.

When you say you daisy chain to multiple ports, do you mean splitting the pairs behind the wall plate and punching each pair down on a different jack?

You should always punch ALL 4 pairs on 1 jack, and use an adapter on the outside of the wall plate...i.e. plug the adapter into the jack and split the pairs with the adapter.

Besides not being able to test when you split them behind the jack, it can be a troubleshooting nightmare. I have cleaned up many jobs that were done that way, and every client I have converted to standards compliant terminations loves the ease of MAC's now. Not to mention my techs love it because to make any changes, they never have to re-punch or open a wall plate. Simply move a patch cord or line cord. We can quickly turn a phone jack into a data jack without any tools.

How do you feel about 96 port patch panels? We quit using them after the first time.. Too difficult for cable management. I like my patch panels to be 48 port and at least 1 RU of cable management between each patch panel.

Keeps things nice and neat that way.


Richard S. Anderson, RCDD A+ Network+ HTI+
http//

http://www,servamatic.net

 

[TelNetSystems]

>> When you say you daisy chain to multiple ports, do you
>> mean splitting the pairs behind the wall plate and
>> punching each pair down on a different jack?

I should have been clearer. When an incoming telco line is used for one thing only, like a PBX trunk, I can simply patch it to the appropriate location and all is well. However, something like a shared modem line may need to be routed to 4-8 different jacks/wallplates. Rather than plugging splitters into the patch panel (and perhaps more splitters into that splitter) in order to connect 4-8 patch cords, I have taken the incoming cable for those telco lines at the back of the patch panel and punched them down to one port with a non-cutting blade, then brought the excess cable around to the next port, punched down there, brought the excess to the next port, punched it there, etc. until the cable feeds as many sequential patch panel ports as I need. Then I label them something like 555-1212(1), 555-1212(2), 555-1212(3), etc. Then I patch the wall jack for the first computer to 555-1212(1), the wall jack for the second computer to 555-1212(2), etc. I hope this is clearer.

I have gone the split pairs route before, and always ended up rewiring them to standards and/or pulling additional cables. Non-standard termination simply isn't flexible enough. As for the 96 port patch panels, they are a little on the large size. I wanted to have 4 port wall plates 1-96 with jacks A-D on them, ie: A001, B001, C001, & D001 on the first wall plate, A002, B002, C002, & D002 on the second wall plate, etc. They turned out to be a a little big in practice, and it would be silly to repeat that mistake just to avoid having jacks with E, F, G, & H on them.

 

[TouchToneTommy]

If I'm going to extend Station Ports and Dial Tones to a patch panel on a rack, it's because of where the switch is mounted that there is not a nice clean way to run patch cords from the switch to the rack. My preference is to use an 8P8C 568-(A or B) panel, (usually just use a Cat-5 panel, no special orders for Cat-3 hardware, and anyway the customer is the one paying for the solution) then run 25 pair cables and punch them down as USOC 2-pair per port. At the backboard end I punch them down on 66 blocks, and mark the blocks with the patch-panel jack numbers. Then cross connect the stations and dial-tones to the blocks so that ALL of the stations are extended to the rack for patching, and also any off-group dial tones for modem/fax/etc. If any of these analog lines are going to be shared, it is simple to loop them to multiple patch-panel jacks back at the 66-blocks. Dial tone into the switch is usually handled by cross connecting from the RJ-21 to the switch directly, instead of going through the patch panels.

 

[TelNetSystems]

I hear from most people that they don't run the telco lines to the phone switch through a patch panel. I assume you still use a cross-connect field between the telco demark and the phone system. Or are you wiring direct from the demark to the phone switch?

I'm also hearing that most people patch directly from the jacks on the phone system to the horizontal cabling patch panels. I don't really see any reason why there _needs_ to be a patch panel on the rack for the telepone switch extensions. It just seems.... cleaner?... more intuitive?. Of course, it also requires the purchase and wiring of an additional patch panel. I'll have to think about that. I assume you add the patch panel back in when using a switch that has amphenol connectors instead of modular jacks? Or do you use a hydra cable directly to the horizontal cabling patch panels?

 

[DToolsDesigner]

Just for the record....The daisy chaining you describe is "bridging" not daisy chaining.

Richard S. Anderson, RCDD

http://www.servamatic.net

 

[TelNetSystems]

Thanks for pointing out the correct terminology. Being able to use the right term generally cuts down on ambiguity and misunderstandings, as evidently happened here.

Thanks again.

 

[daronwilson]

Each installation depends on several factors, including the size of the installation, the cost the customer is willing to bear, the flexibility the customer wants, the type of equipment specified, etc. I have MANY customers that want nothing to do with moving data ports and phone wires. They are in the business of insurance, law practice, medicine, whatever and they make their money doing what they do, not moving phones and computers around. For them, I offer them that service and they pay for it. Others want to be more involved and program the PBX, move their own cables, etc. For those folks, we lay the system out so they can do those functions in house.

A typical small installation for me would be a wall mount swing rack for the data patch panels, wire management, switches, shelf for misc. gear, etc. Data wiring would all terminate on this patch rack.

Telephone wiring would likely land on 110 blocks on a backboard. Depending on the KSU/PBX, it would typically mount on the backboard as well. Assuming the wiring comes out of it on amphenol 25 pair plugs, we would normally run pigtails out of it to 110 blocks. Stations get jumpered with cross connect wire. Depending on the system, moves will be as simple as swapping directory numbers in software no physical changes in the jumpering would be required. Incoming lines from the CO appear on an RJ21 (generally) a 66 block type of dmarc. From there, we would normally jumper them to trunk positions on the KSU/PBX block. Fax lines, modem lines, etc. are jumpered individually to those work station outlets.

Obviously if you are putting in a system that has modular jacks on it, things could be different. Partner stuff lends itself very well to landing the phone wiring on a patch panel and just using patch cords from the KSU. Smaller KSUs with 6P4C plugs don't, so you will either have one type of patch cable for phone and one for data, or you have to rewire the KSU to some 8p8c patch panel.

We used to do those great deals where modem lines were shared all over, and those are a hassle, but rarely do I find anyone doing that anymore. We're wiring them a LAN, there seems to be much less need for modems shared around.

I guess it is primarily what the customer wants within reason. Most of our smaller installations would not lend themselves to a patchpanel for phone in my opinion, there are a some midrange installs that do (call centers are one), and bigger jobs are primarily spec'd and bid however the customer has determined (I don't see many of these requiring patch panels for the phone). I'm primarily in a smaller market though, your individual mileage may vary.



It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com

 

[PhoneGuy2000]

I am always happy to terminate the station, system, and telco ports to a patch panel. I don't always get to design the layout of the switch though and to go to an all patch panel solution increases the cost of materials. I did encounter the scenario you mentioned of putting in splitters and splitters into splitters and decided the next time I needed to bridge/daisy chain some ports on the frame, I might use a seperate 24 port panel below the telco panel strictly for that purpose. I would run cross connects on the IDC on the rear of the panel to as many ports as I need plus 1. Plug a cord from the telco panel to the 1st port and use the other ports just as you have.

by the way, did you gleen your answer to the original question from the post by Dtools.. Use a straight through cord at the system and the reguler telephone line cords at the station. this way the pins of the jack are being passed straight thru to the station and then only reversed once at the user end...

 

[TelNetSystems]

I decided to stick with 8 postition patch panels, even if I only use the two center pins. That way I will not need to stock special telco patch panels and straight-through line cords, and I can use the same patch cords I use for everything else. That also eliminates the potential for getting straight-through line cords confused with cross-over line cords.