Question about wire mapping wire length

[pete_c]

Testing out an old cat5 run.
 
1 - wire map shows all of the pairs are fine with matching numbers
2 - Distance/Length shows
A - Pair 12 151.4
B - Pair 56 133.2?
C - Pair 78 151.4
D - 3 - 185.6 and 4 - 166.6
 
Testing POE I do get the 48 V to the other end
Testing network connectivity and not getting any network connection.
 
Noticed that this cable is cat5 and not cat5e.
 
I also noticed two spots about 1 foot apart and about 1 foot from where it was terminated that it appears to be a bit crushed flat as if it was pinched by the housing?
 
What is the mismatching pair length indicative of?
 
Am I sol regarding using old cat5e for my IP camera?

 

[tmbrown97]

I'd chalk that up to being a $100 tester and just take it as an average... it's well under 300' (assuming that's feet and not meters) so you should be fine for length I'd think...
 
It's hard to say without having a better tester to put on it - but when in doubt, I reterminate ends to make sure they're clean and maybe test again?  And have you tried plugging a laptop in out there to see if it sees the link so you know that the connection is good regardless of the POE status?

 

[Frunple]

5 and 6 isn't a pair.
1-2, 3-6, 4-5, and 7-8 are the pairs.
I'd check the ends, you can usually make out the colors depending on the wire used, make sure they are wired right.

 

[pete_c]

Thanks guys.
 
Yup; tried the IP camera and saw the network LEDs blinking but couldn't ping it.

 

[pete_c]

I see a problem with the cable testing it with the TP-Link switch

 

[az1324]

Try reterminating it

 

[pete_c]

Yup; that worked.  Terminated the inside to the new POE patch panel and reterminated outside. 
 
Odd now all of the wire lengths are fine.  Wire mappings were always OK.
 
I did notice that the colors of wires being solid expediated this endeavor.  Most of my newer catxx cables utilize transparent colors and that makes it difficult a bit to punch the cables down.
 
Are all of the current new catxx cables the same or do they utilize solid colors?

 

[Del91574]

Lengths with a TDR and cat XX cables that skew is indicative of a termination issue (usually).
 
As far as the cascading colors, it varies by manufacturer...some are better for their colors on the individual pairs while others only do the solid and provide the cascading band on one only. The worst offenders always seem to be plenum cables.

 

[pete_c]

Thanks Del!
 
Yup; both had had been terminated with RJ-45's maybe some 10 years ago or so.  Each end had a balun utilized for analog video and power over these last 10 years.  Initially just tested what was there in place.  Odd that I got matched pairs with no crossing over but weird lengths.  Both ends looked fine.
 
Testing again after reterminating both ends and before connecting the POE HD IP camera cabling wire mapping was fine (as before) and all of the lengths are identical.  Guessing it uses signal reflectivity of sorts to check lengths?
 
 I am impressed with my cheap network tool as it does provide a bit more granularity when testing cables.
 
Next endeavor is second berm analog camera conversion to IP POE.  Probably just skip the testing of what is already terminated (RJ45's) and punch it down in the comm room and reterminate the end outside.  It was a waste of time yesterday trying to figure out what didn't work.
 
The view is way better than the analog cams.

 

[tmbrown97]

I believe they use TDR to get cable lengths...
 
The issues likely resulted from dirt or corrosion on the connector or wires - all resolved by trimming off the ends and starting fresh.

 

[pete_c]

Thanks Work2Play.

 

[Del91574]

Time Domain Reflectometer (TDR)....injects a signal and then listens to the reflection back (if any) using a known velocity of propogation for a "typical" cable construction, AWG and type....they're not foolproof and there's usually a % of error in either length to end or to a cable issue. You use it to get length, either total, or to a splice/tap location...branches are where it really won't work.
 
They have cheapies (numerical value) and more pricey units (graphical) and if you know what you're looking at, you can locate the taps/splices on a piece of coax, and in dry pairs, you can do the same to determine if the cable is getting wet, and if you're really anal, in the case of Coax, usually you can see each place it's stapled or secured (slightly crushes dielectric and braid).
 
I usually enjoy bringing them out when a piece of hardware on a site loses connectivity or there's construction....as long as you know the way the cable is run, it's fun to point out where other contractors damaged your cable and then you give them the distance from your location to the damage +/- 5' usually. Usually means a nice backcharge for locating the issue and the repair with irrefutable evidence of the damage, even more fun when the report with the starting footage, damage footage and the piece of damaged cable (with distance on the jacket) is provided. 
 
Speaking of that, I should really sell off my duplicate test equipment.

 

[pete_c]

Thanks Del.
 
Doing the second outdoor run (old cat5e) initially checked TDR and all wire lengths appeared fine end to end with RJ-45's on each end along with the wire mapping.  That said I punched down both sides and retested and all lengths appeared to be identical and wiremapping was fine.
 
I am using the "cheapie" network cable tester I purchased which does fine.  Not using the LED tester anymore. 
 
Just a few years ago helped a neighbor with one cat5e run to one wall pad for his Russound system which was installed during construction some 5-6 years prior.
 
There was no end to end connectivity.  I used a toner to find where the break was; but it was a PITA.  That said contractor had stapled cat5e to an attic rafter then pinched and pulled cable breaking it.

 

[Del91574]

TDR's are a nice tool to whip out besides a network tester/analyzer. Toners work, but only if you have an open cable....the shorts are real PITA's, even with a TDR.
 
Assuming it's a Monoprice dohickey you're running as a cheap Fluke?