alternative to cable testers ?

[Pants]

If I suspected a cable run, (from Ethernet jack to patch panel) is bad, would it be an adequate test to connect a laptop to the suspected jack, and then plug a loopback plug into the patch panel, to see if link lights come on?

For testing connectivity it seems like it would be adaquate, but for testing speed, I'm not sure...ie I guess that's what cable certifiers are for?

 

[Moltuae]

So that you don't need to buy an expensive cable tester you mean?

Well, for a basic test, you just need to confirm that pin-to-pin connectivity is correct. Visually inspect the cable wiring at each end to check the colour order, then use a cheapo tester such as this to check end-to-end continuity.

To verify the connection speed and reliability, well, the proof of the pudding and all that .... try transferring some large files over the connection and check for connection reliability with a few wiggle-tests while the data is transferring.

Obviously using a cable certifier would be quicker/better, but if everything checks out, the connection operates reliably and provides the expected bandwidth, you can be pretty confident you've got a good connection.

 

[Pants]

Thanks. That pin to pin connectivity tester looks like a handy little device..and for cheap!

 

[Mercenary Roadie]

If I suspected a cable run, (from Ethernet jack to patch panel) is bad, would it be an adequate test to connect a laptop to the suspected jack, and then plug a loopback plug into the patch panel, to see if link lights come on?

For testing connectivity it seems like it would be adaquate, but for testing speed, I'm not sure...ie I guess that's what cable certifiers are for?

What you are proposing won't tell you anything and might not even work.

You do not need a cable certifier unless you are doing major cabling installs. What you need at a minimum is a cable mapper. I have used one of these for years before I bought my Fluke CableIQ tester.

http://www.ebay.com/itm/Network-Cab...187?pt=LH_DefaultDomain_0&hash=item20ec59cb43

You can buy extra remotes to give you a total of 8.

This type of cable mapper will tell you how you are wired on each end ( shorted, crossed pair, open, etc.) and it will also tell you the length which is nice to know (if you know the cable is close to 100 ft long and it says it's only 50 ft, you know there is a break in the cable)

This is just an example link, you can find these everywhere.

Stay away from those Idiot LED boxes as they don't tell you much of anything other than the cable has continuity and even then they lie at times.

I upgraded to a Fluke CableIQ tester recently and love it. Do a google search for it. It will cost you about $1000.00 minimum and you can get one off of eBay like I did which was new in the box, with all of the accessories for $1000.00. It has paid for it's self already.

Stay away from the ByteBrother garbage. Thier so called Real World Certifier is anything but.

 

[Pants]

Thanks for the recommendations on the cable mapper.

Why do you think a loopback plug won't work?

 

[YeOldeStonecat]

I agree with what Merc said above....
Plain old "link light testers" are relatively useless...all they tell you is if it's pinned out right...or if the cable got cut by an axe or pair of scissors in the middle and is broken.

They don't tell you how well it was crimped, or length of cable, or if there's any bad interference somewhere along the run which is causing issues. I can't begin to count the hours I've wasted in years past where there was a problem with the cable that a plain old link light couldn't find for me.

That's why we outsource our cabling needs to a pro sub we've used for nearly 20 years. He has the right equipment. Sure I can crimp like a mad man...but I'd rather spend my time doing higher billable rate computer jobs.

 

[tom11011]

I would spend the $50 at Home Depot or Lowes to get yourself a cable tester. Should probably be in every techs tool bag, along with a cable toner.

Alternately, you can do a simple test just by looking at the interface output of most mid to enterprise switches. Have a look at this output on a single port of a cisco switch, tells you everything you need to know about the connection.

PRDSWCLEP01#show int gi0/1
GigabitEthernet0/1 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is 0024.f9e8.29c1 (bia 0024.f9e8.29c1)
Description: EXPEDIENT WAN Connection #1
Internet address is ########
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 1355000 bits/sec, 405 packets/sec
5 minute output rate 3131000 bits/sec, 442 packets/sec
22603332805 packets input, 5096247351329 bytes, 0 no buffer
Received 36770754 broadcasts (0 IP multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 36392649 multicast, 0 pause input
0 input packets with dribble condition detected
38369903117 packets output, 51976812682104 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out
PRDSWCLEP01#