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T1.5 extensions -- Cat5E plenum or 2 pair 24 awg shielded cable 1
- Thread starter bpblore
- Start date
franklin97355
Technical User
It would depend on the situation but the shielded cable would work in harsh environments better than cat5. It also would be overkill in some situations as would the plenum if not run in a air return.
It also depends on if telco gives you a powered span or a low voltage handoff, powered spans are mainly a thing of the past, where it was a copper T-1 span from the CO, and the distance, they could be anywhere from -48 and grd to
-130 & +130, if powered you need shielded, if from a mux or fiber loop converter then Cat5 will do as long as there is no RF generating equipment around.
-130 & +130, if powered you need shielded, if from a mux or fiber loop converter then Cat5 will do as long as there is no RF generating equipment around.
AvayaNovice
Vendor
Shielded cable is always going to be more protected from interference. How far are you extending the demarc, what objects are near your path (ie. lights, electrical equipment, etc)
I've seen it done with Cat-3, jumper wire, etc. Really depends on the application, but for the best bang -- I'd stick with STP Cat-5(e) even though it shouldn't make a difference -- better safe than sorry.
And I'm sure our good friend DW will have some standards based comments for us.
I've seen it done with Cat-3, jumper wire, etc. Really depends on the application, but for the best bang -- I'd stick with STP Cat-5(e) even though it shouldn't make a difference -- better safe than sorry.
And I'm sure our good friend DW will have some standards based comments for us.
Most T1's are terminated at a smart jack to balance the line and mainteain the levels.
This is a digital circuit running at 1.5m. Yes STP is what you used to always see on them, but remember how far back that goes, before the higher speed circuits we use now.
cat3 was designed for 10m and cat5 is 100m. If you have a reasonable length run and it is out of interferences way it
is acceptable to use cat5 cable to make the connection.
This is a digital circuit running at 1.5m. Yes STP is what you used to always see on them, but remember how far back that goes, before the higher speed circuits we use now.
cat3 was designed for 10m and cat5 is 100m. If you have a reasonable length run and it is out of interferences way it
is acceptable to use cat5 cable to make the connection.
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- #6
daronwilson
Vendor
Well I wouldn't want to let the novice down, but I'm not sure I have a standards based response.
STP (Screened Twisted Pair) Cat5 is probably going to be better than UTP, but not the best choice. If we are talking about extending from the smart jack, using 2 pair individually shield DS-1 wire (specifically designed for this application) would be my first choice.
As the T1 makes it's way to you from the Telco, it is likely that they put the transmit pair in one binder or group, and the recieve pair in another binder so that the two are physically separated in the Outside Plant Cable. This is done to prevent interference between pairs.
The smart jack give the telco a place to terminate and make the dmark for you, it also provides some amplification and conditioning, and provide the ability for the telco to check their circuit to that point. After that, you have a limited distance you can extend that circuit without conditioning, and that may vary depending on the type of wire you use.
I've extended them short distances with Cat5 no problem (from the smart jack on the backboard 10' to the CSU/DSU), and when the distance is longer or there is potential noise sources on the path, I use the DS-1 type cable. It is two pair, individually shielded, different construction than screened Cat5. Be sure to properly ground the shield, if you dont, you have a big long 'antenna' surrounding your data wires that will grab stray RF and couple it to your data wiring.
It's not always about standards, many times it is just about using the product designed for the application.
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
STP (Screened Twisted Pair) Cat5 is probably going to be better than UTP, but not the best choice. If we are talking about extending from the smart jack, using 2 pair individually shield DS-1 wire (specifically designed for this application) would be my first choice.
As the T1 makes it's way to you from the Telco, it is likely that they put the transmit pair in one binder or group, and the recieve pair in another binder so that the two are physically separated in the Outside Plant Cable. This is done to prevent interference between pairs.
The smart jack give the telco a place to terminate and make the dmark for you, it also provides some amplification and conditioning, and provide the ability for the telco to check their circuit to that point. After that, you have a limited distance you can extend that circuit without conditioning, and that may vary depending on the type of wire you use.
I've extended them short distances with Cat5 no problem (from the smart jack on the backboard 10' to the CSU/DSU), and when the distance is longer or there is potential noise sources on the path, I use the DS-1 type cable. It is two pair, individually shielded, different construction than screened Cat5. Be sure to properly ground the shield, if you dont, you have a big long 'antenna' surrounding your data wires that will grab stray RF and couple it to your data wiring.
It's not always about standards, many times it is just about using the product designed for the application.
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
AvayaNovice
Vendor
Oh, but isn't the product designed for the application THE standard? 
I still say Cat-3 is OK. I've seen that done many times over a block into a 25 pair... without a single problem.
For a T1 -- especially, coming out of a smart jack, no problem... but why not go the extra mile and be safe using DW's almighty STP (which I thought meant shielded twisted pair?)
Good point on grounding the shield.
I still say Cat-3 is OK. I've seen that done many times over a block into a 25 pair... without a single problem.
For a T1 -- especially, coming out of a smart jack, no problem... but why not go the extra mile and be safe using DW's almighty STP (which I thought meant shielded twisted pair?)
Good point on grounding the shield.
daronwilson
Vendor
Geez you sure have an issue with standards. Ethernet is a standard, has nothing to do with the 'product designed for the application'. The 'standard' was defined by a working group so that it could be implemented everywhere and have interoperability, but I suspect you already knew that
Back to the task, my typo on STP, it is shielded twisted pair, and ScTP is Screened Twisted Pair. The standards for telecommunications cabling recognizes either UTP 100 ohm 4 pair OR ScTP 100 ohm 4 pair for horizontal data cabling (note, no STP here). Also, there is a clause allowing STP-A (150 ohm shielded cabling, old IBM type) for existing installation, but not recognized for new installations. I believe the Cat5e you find with a shield is likely labeled ScTP.
But that is the nice thing on this forum. When you pose a question, you get lots of ideas. I have no problem with giving many options, I usually try to offer a top quality standards compliant solution as well as several work arounds that function well. What frustrates me is completely incorrect answers (there have been several pinout questions with answers that were just physically wrong and non functional).
Again, depends on the customer, cost, reilability, etc. Personally I enjoy coming in to a new customers area and seeing half assed installations, makes doing it right for them all the better. I've done my share of cheating to get it in down and dirty, but given the choice I'd like to do it right.
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
Back to the task, my typo on STP, it is shielded twisted pair, and ScTP is Screened Twisted Pair. The standards for telecommunications cabling recognizes either UTP 100 ohm 4 pair OR ScTP 100 ohm 4 pair for horizontal data cabling (note, no STP here). Also, there is a clause allowing STP-A (150 ohm shielded cabling, old IBM type) for existing installation, but not recognized for new installations. I believe the Cat5e you find with a shield is likely labeled ScTP.
But that is the nice thing on this forum. When you pose a question, you get lots of ideas. I have no problem with giving many options, I usually try to offer a top quality standards compliant solution as well as several work arounds that function well. What frustrates me is completely incorrect answers (there have been several pinout questions with answers that were just physically wrong and non functional).
Again, depends on the customer, cost, reilability, etc. Personally I enjoy coming in to a new customers area and seeing half assed installations, makes doing it right for them all the better. I've done my share of cheating to get it in down and dirty, but given the choice I'd like to do it right.
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
mikeydidit
IS-IT--Management
I'll give you a star on that one DW. There are many ways to do anything. The right way should also be considered an option....
Mikey
Mikey
AvayaNovice
Vendor
I knew that about standards... I was trying to make some kind of pun, but whatever
And yes... this board is helpful because while the standard does exist, implementing that standard involves a lot... and lots of the guys (and gals) who are on here have a lot of good tips and shortcuts to get the job done right, faster.
And with that... I say we use jumper wire for 100Mbit networking. How about that for a new standard
Off topic ceases...
And yes... this board is helpful because while the standard does exist, implementing that standard involves a lot... and lots of the guys (and gals) who are on here have a lot of good tips and shortcuts to get the job done right, faster.
And with that... I say we use jumper wire for 100Mbit networking. How about that for a new standard
Off topic ceases...
I sure hate to stir the pot but just can't resist in this case.
avayanovice it is not "STP Cat-5(e)" that is used at all. When they came up with the "standard" as you want to hear, cat 5 did not even exist. The standard cable to use is a 2 pair, individually shielded pairs just like Daron said.
avayanovice it is not "STP Cat-5(e)" that is used at all. When they came up with the "standard" as you want to hear, cat 5 did not even exist. The standard cable to use is a 2 pair, individually shielded pairs just like Daron said.
OK, may I add some info that may help put into perspective how different situations call for different solutions.
In most cases we have extended T-1 circuits using Cat 5e. The telco leaves the smartjack and our equipment is usually not far away. Seldom, if ever, have we had a problem.
Now, I have one unique customer who has two buildings. The telco cable terminates in building #1 which is closest to the street. However, all of the equipment is located in building #2, which is 700 feet away. There is a 100 pair OSP cable between the two buildings. The smartjack is actually located in building #2 on the second floor (where the router is).
So, telco comes into bldg 1, runs up to bldg 2 on house cable, extends within bldg 2 on inside wire and terminates on a smartjack. The customer recently added a second T1 in the facility for data only and have had some intermittent problems with cutoffs (voice) and outages (data). Could it be that the two circuits in one cable over such a distance is problematic? If so, what is the solution? Seperate 2 pair shielded cables between the buildings? Insights are appreciated
Randy
In most cases we have extended T-1 circuits using Cat 5e. The telco leaves the smartjack and our equipment is usually not far away. Seldom, if ever, have we had a problem.
Now, I have one unique customer who has two buildings. The telco cable terminates in building #1 which is closest to the street. However, all of the equipment is located in building #2, which is 700 feet away. There is a 100 pair OSP cable between the two buildings. The smartjack is actually located in building #2 on the second floor (where the router is).
So, telco comes into bldg 1, runs up to bldg 2 on house cable, extends within bldg 2 on inside wire and terminates on a smartjack. The customer recently added a second T1 in the facility for data only and have had some intermittent problems with cutoffs (voice) and outages (data). Could it be that the two circuits in one cable over such a distance is problematic? If so, what is the solution? Seperate 2 pair shielded cables between the buildings? Insights are appreciated
Randy
daronwilson
Vendor
Generally everything between the smart jack and the telco is their responsibility. Even if they run it on house cable or the existing tie cable, it is their responsibility to the dmarc which should be the smart jack.
Also remember that the line conditioning, amplification, etc. takes place up to the smart jack. They have the ability to control repeater levels along the way and should engineer the circuit so that you have a usuable connection at the smart jack.
When using higher count cables, normally, they will send transmit in one binder and receive in a completely different binder. Often if there are problems, a good engineer will look at the type of cable and determine the most separation for the transmit and receive. For example, in a 100 pair cable, there will be several sets of pairs that are opposite each other and nearest to the jacket. Cable manufacturer data sheets can show you the make up of the cable, so you can see that for example maybe Pair 30 and pair 90 are on complete opposite sides of the cable yeilding the most physical separation.
Now...here is why I like to do it right. Your customer calls and says we're having dropouts, you show up with the telco to sort it out. It is really nice to be able to say that you used DS-1 cable (if required for the distance), specifically designed for T1 circuits from the smart jack to the CSU/DSU. It is not any fun to have the telco do a loopback or stress test, tell you it is ok, and tell your customer that the connection from the smart jack to the router is in question.
So back to your problem. First I would confirm that my cabling was good from the T1 smartjack to the CSU/DSU. Possibly swap cables between the two T1's and nothing else and see if the problem follows the cable. Next, I'd see if the telco can look at the circuit, and certainly get them to loop it back and test it. Ideally, stress testing it would be good (they throw test gear on the line and simulate a full channel of data for 30 minutes or more and check for any bit errors). Again it is always nice to have ruled out any suspect wiring on your side before calling in the telco for testing, and just swapping cables may be the simplest way to do that.
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
Also remember that the line conditioning, amplification, etc. takes place up to the smart jack. They have the ability to control repeater levels along the way and should engineer the circuit so that you have a usuable connection at the smart jack.
When using higher count cables, normally, they will send transmit in one binder and receive in a completely different binder. Often if there are problems, a good engineer will look at the type of cable and determine the most separation for the transmit and receive. For example, in a 100 pair cable, there will be several sets of pairs that are opposite each other and nearest to the jacket. Cable manufacturer data sheets can show you the make up of the cable, so you can see that for example maybe Pair 30 and pair 90 are on complete opposite sides of the cable yeilding the most physical separation.
Now...here is why I like to do it right. Your customer calls and says we're having dropouts, you show up with the telco to sort it out. It is really nice to be able to say that you used DS-1 cable (if required for the distance), specifically designed for T1 circuits from the smart jack to the CSU/DSU. It is not any fun to have the telco do a loopback or stress test, tell you it is ok, and tell your customer that the connection from the smart jack to the router is in question.
So back to your problem. First I would confirm that my cabling was good from the T1 smartjack to the CSU/DSU. Possibly swap cables between the two T1's and nothing else and see if the problem follows the cable. Next, I'd see if the telco can look at the circuit, and certainly get them to loop it back and test it. Ideally, stress testing it would be good (they throw test gear on the line and simulate a full channel of data for 30 minutes or more and check for any bit errors). Again it is always nice to have ruled out any suspect wiring on your side before calling in the telco for testing, and just swapping cables may be the simplest way to do that.
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
daronwilson
Vendor
Here is a link with some info about telco color codes as well as pinout and wiring suggestions for T1:
As I re-read my T1 A Survival Guide written by Matthew Gast and published by my all time favorite O'Reilly here is what he has to say about extended demarcs:
In situations where the smart jack is far away from the CSU/DSU loation...wiring must be run from the demarc at the smart jack to the CSU/DSU location. This is called an extended demarc. Extended demarcs can be tricky to get right and are a major source of problems with T1 circuits. Wiring an extended demarc is not as simple a task as installing an Ethernet drop. In many cases, shielded cable must be used to preserve signal quality. Additionally, the pinout for the smart jack interface is different from other data-communications pinouts, so unless the installer is familiar with the pinout, the line will pick up outside interference.
Hope that sheds some more light on it, the link above is a pretty good page for color codes and pinouts.
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
As I re-read my T1 A Survival Guide written by Matthew Gast and published by my all time favorite O'Reilly here is what he has to say about extended demarcs:
In situations where the smart jack is far away from the CSU/DSU loation...wiring must be run from the demarc at the smart jack to the CSU/DSU location. This is called an extended demarc. Extended demarcs can be tricky to get right and are a major source of problems with T1 circuits. Wiring an extended demarc is not as simple a task as installing an Ethernet drop. In many cases, shielded cable must be used to preserve signal quality. Additionally, the pinout for the smart jack interface is different from other data-communications pinouts, so unless the installer is familiar with the pinout, the line will pick up outside interference.
Hope that sheds some more light on it, the link above is a pretty good page for color codes and pinouts.
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
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