Making sure about a T1 cable

[RandyVSP]

OK, I have the opportunity to clean up a major mess in my comm room, and want to make sure I understand my T1 cables, from Dmarc to my router case.....

If I run a CAT5 cable, using 568B standard, RJ45 etc on both ends, that should work!?!?!?

I have the pinout as 1 - ring, 2 - tip 3 - rx gnd
4 - ring, 5 - tip, 6 - tx gnd

Am I OK using CAT5 cable? run is across my room, about 50 feet max.....

Also, any problems running several of the T1's side by side with CAT5 LAN????

Thanks in advance,
Im a radio monkey learning my way into the data dummy realm.
Randy

 

[Mongo5150]

Yes, using 568b on both ends will work fine. For a T1 you only need 2 pair. Pins # 1245(blues and oranges) Cat 5 cable is fiine for extending it. I would recommend, if you are using plain old cat 5, to use a seperate cable for each T1. If you have cable that has 1 or 2 pair sheilded, then you could run 1. But without sheilding, you may or may not get X-Talk.(are you a good gambler?)

 

[lopes1211]

I usually run 1 Cat-5 for 4 TX's and a 2nd Cat-5 for the 4 RX's to get 4 T-1's on 2 cables and minimize X-Talk.

-CL

 

[Bobg1]

Look at it this way. Cat5 is capable of handling 100m
your T1 is only 1.5m
So cat5 cable is more than enough.

 

[OldPhoneGuy]

Cat5 works just fine for T1.

 

[daronwilson]

Just because T1 is only 1.5mbs and Cat5 is 100mbs is not a really good excuse to use Cat5 for T1. I too do it, whenever the customer needs something extended quickly or the cheapest. However, the proper way is DS-1 cable which is individually shielded pairs, one for transmit, one for recieve.

Cat5 seems to work fine for short distances, though I've never thrown any expensive equipment on it to confirm it at longer runs. However, the encoding schemes, framing, signal levels, etc are different on the two circuits, they are very different types of circuits. Remember that depending on which pairs you choose for T1 signals the transmit pair may be considerably longer than the recieve pair due to different twist rates in Cat5 type cabling. It is possible this could cause a problem at some length of cable.

In my opinion, Cat5 is fine for extending a T1 from the Dmarc to your CSU/DSU under 50 feet or so provided there are no interference issues. I guess....there is a reason they make DS-1 type cable, and there is a reason it is used for T1 type circuits. We use this cable in longer runs, high EMI/RFI environments, etc.

Good Luck!


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

 

[OldPhoneGuy]

On the other hand, it is perfectly acceptable to extend T1 using plain old Cat1 house cable as long as you run your transmit and receive pairs in different 25 pair binders. The RBOC's do it all the time.

 

[daronwilson]

Yes it certainly is...so long as you do that BEFORE the smartjack. The smart jack has amplification and equalization as do the other repeaters along the way from the Telco. The RBOC's job is to make sure that it is balanced, amplifed and error free from dmarc to dmarc. It's obviously just my opinion, but when the customer calls you and says they are having T1 problems, you bring the telco in and they stress test it from their Dmarc and it is fine, then you hook up your regular telephone cable to it and have problems, you may not look so cool. When you extend your circuit past the dmarc, you don't have the ability to change amplification and adjust equalization as needed to compensate, so unless I have the test equipment to make sure it is all perfect at the extended dmarc, it is usually not worth the risk to me.



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