sundance-communications.com/forum Forums General General Telephone & Systems Information Multi-Line Phones on cat5 (no switch)

I am helping a friend setup his phone and computer network for a new business. I am familiar with the computer side, but I need some help on the phone side. He has ordered 4 analog lines. There is no phone switch -just multi-line phones. There will be 6 or seven stations using this phone: https://www.radioshack.com/sm-rca-4-line-expandable-phone-system--pi-2172379.html.

We are running a cat5 to each station and will be terminating it in the standard computer fasion with a RJ45 connector.

My question is how to get the cat5 termination to go to L1/L2 and L3/L4. Do I need to make my own cables or will I be able to find an adaptor to do this?

Any other tips in this area would be appreciated.

Thanks,
Jeremy.

Jeremy:

Boy, you surely got the wrong person to answer this question (I hate the use of the term RJ45; it's a misnomer). That's a separate issue and I am here to actually offer you some assistance, not to beat you up!

First, these phones use two separate RJ14 connections, one for lines 1 and 2 and the other for lines 3 and 4. There is no easily-accessed "RJ45 to two RJ14" adaper.

Using category 5 cable for this application is complete overkill, but it will still work. The cable itself can be used, but two separate jacks will likely be your quickest solution to the problem.

You will need two separate jacks at each phone's location, both configured as RJ14's. This means that the following pin assignments will be required, assuming you are using 8-position jack modules:

Jack #1 (Lines 1 & 2):

White/blue pair (Line 1): Pins 4 & 5
White/orange pair (Line 2): Pins 3 & 6

Jack #2 (Lines 3 & 4):

White/green pair (Line 3): Pins 4 & 5
White/brown pair (Line 4): Pins 3 & 6

There may be some commercially-available adapters or cords to accommodate the dual-line cord arrangement necessary to install these phones, but they won't be something you can obtain quickly on a consumer level.

There's another restriction to consider when installing these types of phones; In general, it's assumed they will be installed using a continuous "loop" of cable, as in one single cable delivering all lines to each jack location. This is typical in residential installations, where these phones are really intended to be used.

In a "star" environment, as in individual home-run cables, they might not perform well. This is not necessarily due to a fault in the phones themselves. The "system" they use typically won't work well on a wiring network that includes more than 600' of TOTAL wiring.

AT&T model 4-line phones (a lot of Radio Shack phones are manufactured by the same manufacturer) state this in their troubleshooting area of the installation manual. 600' sounds like a lot, but when you take seven or eight individual cable runs plus cords, it's not so difficult to overload this limitation. Don't forget that even if you are within this limit, what happens if someone adds a pair of 25 foot cords to move a phone? Then ALL phones start acting up and it's nearly impossible to locate the problem.

Your friend should seriously consider another phone system alternative, such as one that uses a central key service unit. I think that unless they are only using a handfull of these types of phones, you will be dealing with a lot of headaches.

You said it!! You can spend more on trouble shooting
than the cost a real system. Not mention when you need a 5th line and have to throw out those 4 liners.

So if you are comitted to using this system, just run TWO cat-5 to each location. You wouldn't split a single Cat-5 into 2 10BaseT connections, would you?

Thanks for the advice. We are going to work on this tonight. I will measure this out first

I know a star topology sounds silly. This is a temperary solution that I advised him against. This system is intended to hold until he goes voip company wide (12-18mo).

I really want to use 8-pin adaptors -keeping the future in mind. I found some adaptors at https://www.hometech.com/techwire/tpconn.html#UC-40108C, but I am sure if I can use the standard "B" termination and use them. I really want to keep this ready for the voip system -instead of having incompatable ports everywhere.

If I run two cat5 to each phone, I assume this does not approach the 600 foot limit faster than a single cable?

The 600ft rule counts only the active pairs, but you knew that already.

FWIW, I've run AT&T 944's off a single Cat5E cable (blue/orange in one jack & green/brow in the 2nd). For a short-term solution, it works fine. You just need to leave enough extra slack at the wallplate to be able to re-terminate to a single data jack later.

You could use the 40108C's from that web link and just wire everything 568A. Potentially less labor down the road.

Again, no matter what direction you choose to go, leaving lots of slack at either end is the name of the game here.

Steve,
Thanks for the help. I'll go with the 568A on the voice /w the 40108C's for now. The slack is a good idea.

I was thinking about terminating the data cables as 568B. This is what I have always done and I am not sure what would happen if I used A instead (nothing as long as the termination is the same on both ends nothing). Or should I follow the standard and do 568A throughout the whole building?

The only difference is which pair color you'll use for your 2nd line...A white/orange B white/green..As you stated as long as it's the same on both ends. Ed was telling you how to do it with using one cable as he stated your using pins 4,5 and 3,6 to get your two lines on the modular jack to the phone.

All it takes is to get all lines to all jacks in the same place. The adapters aren't FCC legal, but hey, we all drive a few miles over the posted speed limit. It's not like the "phone cops" are coming to get you if you use them, but don't expect any level of reliable service.

Not to sound like a fart in church, but you are going to be dealing with many headaches if using more than five of these phones on the same group of lines. The more phones, the more phantom problems.

Talk your friend out of these things as quickly as you can. They are meant for a few phones in a home environment, not a real office despite the way they are marketed. Radio Shack sells 99.9% to homes/end users; they don't design their products for the rigors of a true commercial environment.

Do what you can to save your friend some money.