Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations SkipVought on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!

RJ-45's instead of RJ-11's for voice 1

Status
Not open for further replies.

nessman

IS-IT--Management
Oct 17, 2006
537
0
0
US
Watching one of my competitors cable up some new construction for a customer of mine (they outbid us for the cable job). They're using RJ-45's for voice drops instead of RJ-11's ("that's because we're using CAT5e cable for voice"), and they're mounting them upside down with the pins on the bottom instead of the top.

I can see my customer is getting what they're paying for.

So... you have the risk of someone plugging their computer into a voice jack - with the risk of a.) frying the NIC and/or b.) crossing pins in the jack if it's not put in properly.

There's two ways of doing a job - the right way, and the wrong way.
 
Medium sized hospital here.
We run white cat5e for voice, terminating in white rj45 jacks on one end and all 4 pairs laid down on 110 blocks or 66 blocks, on the other end. That way if we need another phone we're pretty much ready to go.
For data we use blue cat6 and blue rj45's rated for cat6. IT guys know this convention and so does the phone man (me). Subscribers better not be into any of that stuff. But we're not hardnosed, it just won't work if they screw around with it and get it wrong.
Never had an issue with -48v or -96v hitting the computers.
Analog wall phones are the only rj11 jacks around here.
And no problems.
 
20 years and have never seen a phone jack damage a PC or vice versa.

Lots of ATT/Lucent/Avaya sets use aditional pins even still today. Power on 7&8 for expansion modules on digital sets. Consoles also need power on 7&8. Lots of the phones like 8410's come with 8 conductor cords which wont fit into Rj11 jacks. 8410's will work on a single pair digital on 4&5 OR a 2 pair digital on 1,2,3&6. Finding 300 Rj11 cords during a Friday night move can be difficult even if you're only using 1 pair.

Bottom line, there is noting wrong with 8 conductors on a voice jack. Mounting all of the plates upside down seems a bit unusual though.

Never seen an RJ11 cord damage an 8 conductor jack either. Avaya actually provides RJ11 cords with digital sets yet the digital sets have an 8 conductor socket on the bottom so you can switch to the 8 conductor cord for power once an expansion module is needed. They are not providing a cord with the phone that's going to damage the 8 conductor socket. They would be making themselves liable for damaging every phone they sell.







-CL
 
AT&T/Lucent/Avaya used 8p8c jacks for station ports and system phones on Partner equipment in order to allow people upgrading from Classic Merlin systems (206/410/820/820D) to reuse existing cabling. Partner MLS/Euro 1/Euro 2 sets require only 2 pairs of wires and new installations are generally done with 2 pair cabling and 6p4c station jacks.

I [love2] "FEATURE 00
 
Hi, over here in little old N.Z, we just use rj45 for all cabling wired to a patch panel. We then wire the phone system to patch panels and use standard patch leads to connect. We use pins 4&5 for our 2wire digital and analog cuts so no issue plugging nic card in by accident as it is using 1,2,3&6. The only issue we have is 4wire Panasonic, they will shut down the digital ccts if a computer is plugged in them by mistake. Nic cards are pretty resilient, I've not seen one damaged yet by plugging in to the wrong port.
 
As a customer I would expect to see RJ11 jacks if cat3 was run and rj45 if cat5 or better.
If you are using cat5 my vote is it's a data drop and should be treated as such, even if you are using it for telephones.

For 20 years I have never heard of frying a NIC either. As Cody mentioned most phones use pins 4 and 5.
I think they still make 66 blocks with RJ45's on them.

 
While single line telephones (SLTs) use pins 4 & 5 of an 8p8c jack, choosing a 6p4c jack would seem to be the way to go for such an application.

I [love2] "FEATURE 00
 
Most of the office space I deal with now is frequently changed around or re-purposed. For that reason, a lot of plans are specifying 8p8c jacks irrespective of end use and nothing less than 5e cabling irrespective of use. I use a plastic insert that reduced the 8p8c profile to that of a 6p4c jack like this:
This way, I can designate an analog voice jack that rejects a patch cable, but if the use changes, instead of re-punching a new jack, I just pull the reducer insert. My experience with the inserts is that in addition to the visual cue that it is not a data jack, it keeps the plugs aligned so that there is no damage to the pins when a 6p4c is inserted. I do not presume to suggest this is "right" or "wrong" as such. I am presenting it as one option. One benefit I have enjoyed with this is that when changes are needed and this method is used, the cabling is very predictable as every 4 pair cable is terminated to the same standard and when I do the certification tests, all 4 pairs get passed during one test, and when a jack is changed from analog voice to data, I do not need to re-certify the run because one or two pair that were not used in the 6p4c are then re-punched into a 8p8c jack.
 
dont plug a pc into a key port on a ip office as it will blow the card we have had cust do this twice now
 
Some of the early systems blew a fuse if you just looked at it crosseyed, Intertel being notorious for doing that. The Comdial Executech was one of the first systems that used protection on the ports so a short would take out either the power or the data mate, but not the whole system.

Of course, in those early systems, nobody was doing structured cabling, so you wouldn't spring the expense of 8-pin jacks for voice. We still try to split the cables, leftovers from the old days, where we terminate only 2 pairs on a 6-pin jack, but leave slack so the cables can be reterminated on 8-pin jacks in the future.

LkEErie
 
yes its a giant waste of money to use data jacks for voice and terminating them on patch panels unless the customer
is going to move to a ip system . 6 pos jacks stop morons from plugging data plugs into telephone system
 
I thought you guys would be interested to know that in Australia the standard telephone outlet is now an 8P8C ( I don't use the term RJ45 because that specifies how it is wired and is a Telecommunications designation not a data one) With a structured cabling system all cabling should be interchangeable and in OZ most if not all new installs are purely cat 5E or above even in domestic installs! In fact we have just started rolling out a new national broadband network using fibre to the home that will see our copper network retired and I believe the lowest standard cable from the network boundary will be cat6!

See here for a typical Australian thread on cabling


Please note, in australia cablers must be licensed so there is no discussion on the how to's there!
 
Speaking as a member of the in-house IT/Telecom team for a rather large firm (offices in 14 cities around the globe and 6,500+ phones), we have demanded Cat5 (5e)& RJ45s. They are not color coded; all jacks are white. Our rationale is basically to allow us to 'repurpose' a jack at any time.

All offices are cabled in a very uniform manner. Each "drop" is ALWAYS a 4 port drop, with the exception being wall phones in the elevator lobbies. The 4 port face place is labeled with a Floor # and "Drop #" -- so a cable plugged into the third port on the quad "21-014" indicates it terminates to the 21st floor IDF, jack #014, and being the 3rd port, it will go to the "C" patch panel.

In the IDF, we can can patch that to either a network switch, a voice riser patch panel, ISDNs (legacy VTC equipment), or even to a serial port, as needed. Traditionally, the first jack ("A") on the quad is always a the phone. The last port ("D") is data. As additional data ports are needed, they move to C, then to B.

The legacy PBXes were cross-connected at a 110 block to the Voice Riser patch panels.

This flexibility allowed us to transition our offices from legacy TDM PBXes (Nortel Meridian Option 11c / 61c) to a VoIP solution quickly and easily -- no additional cable drops needed. On the night of the cutovers, only thing needed was to move patch cables from the voice riser patch panel to the new VoIP VLAN switches while a tech swapped out the physical phones at the desks. No new cable drops, no changing jacks from RJ11 to RJ45. The transition in each office was pretty quick, smooth and seamless.

Also, we do not ever use the the PC port on the back of a VoIP phone. The issue with using the VoIP phone as a network switch is that if the phone reboots for any reason (i.e. configuration changes), it takes down the PC's network connection until the phone restarts completely. Interrupting a PC's connection, even momentarily, is to be avoided at all costs in our firm.

The idea it to cable for almost any possible need. It is very very rare that we ever have to call a cable vender to add additional drops in any of our offices, after the initial build-out.

We have used this as our firm standard for well over 15 years and I can't think of any reports of damaged equipment resulting from someone making a cabling mistake. Worse case has been reports of "not working" and the local tech comes by and plugs in the device into the correct jack then walks away -- no damage ever.

==================================
<INSERT SIGNATURE HERE>
 
Its all fun and games until someone plugs my computer into phone jack and fries my main board.
 
It would only be a problem if you pluged into a gigabit network not a 10/100 Base T network they don't use pins 4 &5 that would be used for telephone.
Giga bit uses all the pairs
fiber is better
 
Actually if you look back at where we have come from in telecom AT&T Bell Labs went radical in creating what would be known as the T568B standard. Initially it was used as thier proprietary wiring diagram using 4,5 and 1,2 for digital telephones and requiring 7,8 to be connected for OHVA. If 3,6 were used I dont remember it. This was produced at the end of the 1A2 era and was far more econimical than 25 pair minimum per station. The use of Cat 5cable for voice and data is quite common today so it only makes sense to terminate it on C5 jacks. All that is needed to convert to voice cabling to data for VoIp sets is retermination in the phone room. If the jack is pins down so what its a jack it doesnt look right to the .1% of the population that are phone guys but users dont care. As well many companies have corporate policies that restrict telecom from being on the corporate data network so the into the phone out to the computer deal isnt ok. I guess to sum it up if you got outbid fine, either they lost money if your price was spot on or you're charging too much and pricing yourself out of the market. Either way it will work itself out in the end.
 
My Bad 12 36 for the AT@T digitals with 7,8 OHVA that is if I am remembering 20 years ago correctly, then again something else is screaming violet/slate is ground and none of the lights red or white will light without it. Course might be black/slate too lol eh just ground it to the chassis you will be fine.
 
Try not to post after the Presidential debate drinking game in the future okay?

LkEErie
 
Heck, I remember when trunks had 6 wires T,R,S,C,E,M and carrier systems (when they were used) were K or N Carrier, and you connect wires not with a punch tool or wire wrap gun, but a 400 watt soldering iron.
 
You lost the contract because the compition offered something better so quit your whinning and pull up your panties and get back to work....
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top