Phone wiring question: RJ11 to RJ45

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On Sat, 14 Oct 2006 23:08:26 -0500, Jim Redelfs

Satellite internet cannot support VOIP, because of excessive latency. It takes over 600mS for the signal to get through (considering the distance to synchronous orbit).

I think you can call people but not talk to them. You might hear them complaining about that.

I considered getting VOIP, but was worried about quality and reliability. The POTS system is very reliable. Cable has more outages. Instead of the highly reliable phone line, you get a not-so-reliable ISP and a less-than-reliable VOIP provider.
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71 days until the winter solstice celebration

Mark Lloyd
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wrote:

internet over sat supports it okay. I know, we use it at several sites. The problems is has aren't due to the sat connection per se, but just due to too many hops. Google 'Tachyon' for specifics.
aem sends....
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Hehehehehe! Thank-you, Geordi!
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JR

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CraigT wrote:

Yes, an RJ11 plug will fit in an RJ45 socket. The center pair of an RJ45 jack is reserved for telephone, even though it's seldom used that way. It's up to you to wire it up.
Bob
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wrote:

I've often heard that it's not a good idea to have telephone and ethernet in the same cable. That's why some people install TWO cat5 cables everywhere. The wire assignments (different pins for ethernet and phone) help prevent damage caused by plugging something in wrong.
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What you are trying to do makes sense. MOST new installations create a DEMARK point on the side of your residence that disconnects THEIR network from YOUR wiring. If any service calls occur, they REALLY want to find that demark point and test the line TO YOUR HOUSE. Then on problems INSIDE will cost YOU money, anything TO THE DEMARK from the street will be fixed at no charge.
So, using this same DEMARK location, you can simply insert these 8-conductor to 8-conductor junction point, and then disconnect it while you are using VOIP. Remember, VOIP will be 'driven' by a VOIP router insdie the house, presumably fed by a cable modem. (Can't cut the DEMARK wires if you are actually using DSL).
So, if you have a cable modem, feeding a VOIP router, then simply make the break so it can easily be restored in the future, and then just feed the POTS jack on the side of the VOIP router into your existing house wiring, making sure the 'hot wires' are locted on the CENTER TWO PINS, RS11, RJ12, RJ45, whatever the jack is, it will ALWAYS be the center TWO pins carrying LINE-1 on a analog jack.
Should work fine, and then all telephones which work today on your wiring will contiunue to work.
Note: You may have a RINGER loading issue is using many OLD phones in your house today. They carry a REN value which basically states how much current the ringer takes. A VOIP router can only supply a a total of perhaps 2.5 REN (adding up all of the REN numbers printed on each phone label).

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Ringer Equivalence Number

When The Big Split<tm> came in 1984, the dual gong electromechanical ringer in the Western Electric Model 500 (old, black, rotary dial, desk phone) was used to set the baseline for the REN. The 500 = 1.0 REN.
However, with the virtually complete takeover by electronic ringers, the REN has become mostly useless. They all have a modest REN, rarely over 1.2, but many don't even register using an old ringer test: Using a plain VOM set to Ohms, repeatedly reversing lead polarity. The amount of needle deflection indicates the number of ringers. Many electronic telephone devices with a REN of .8 (for example) won't even make the old VOM budge. Weird. Given that, MANY more electronic ringer-equipped phones and devices will ring/answer than is otherwise indicated by the sum of the indicated RENs.
In the old days, electrically disconnecting the ringer from an illegal telephone set actually WOULD elude a telco attempt to determine the number of phones on a line.
Soooooo... Someone just said the center, two pins of an RJ45 jack are for POTS phone use. Does that mean they are NOT used in for ethernet? If yes, can I run POTS *AND* ethernet over the same Cat5 4pr? If yes, what are the implications to ethernet performance, if any?
I was told the other day that Cat5 is NOT absolutely necessary to run ethernet. Given that, what can I expect if I run a basic (modest) network using the older wire in my 1991 (RBOC gray-sheathed 6-pr, probably Cat3)? TIA
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JR

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On Sun, 15 Oct 2006 09:20:48 -0500, Jim Redelfs

Ethernet uses two pairs: one on pins 1&2, the other on pins 3&6. Most (single line) phone connections use one pair (4&4 on a RJ45).
BTW, I've wired a few ethernet cables, They won't work reliably unless you get the pairs right (pins 3 & 6 must be connected to the 2 wires in the same pair).

You could, but it's not a good idea. If you're putting the cable in, it's not that much harder to run 2 than it is to run 1.

Phone uses voltages up to about 125V (during ringing). A short in the cable could damage your ethernet equipment. Also, the phone can cause interference to the ethernet. You could find your network much slower (many retries).

A 10mbps network is likely to work. Any faster one may not. The twisting is important.
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CraigT wrote:

You're confused. The VoIP adapter sits between your internet connection and the telephone system. The wire that comes OUT of the VoIP box IS a telephone line and should be treated in all ways as another telephone trunk line.
In our case, we have three VoIP modems connected to the network router. Each of the outputs from the three VoIP modems then goes to our PBX system, just like the wires from the telephone company do. To the telephone user, they look exactly like an additional telephone line.
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normal residential demarc, with the rj-11 jacks- he has one of those aluminum or gray boxes with the brass posts for the 4-pair incoming, that also has posts or punchdowns for the runs to all the rooms. Or maybe he has a 66 block, with no apparent terminals or ground blocks upstream. Not uncommon a few years ago for multi-line or multi-residence service. He wants to break the 4-pair telco feed wire, so he can use the inside wiring as distribution for his VOIP dial tone from the VOIP box.
Telco will get cranky if OP cuts 'their' wire, if this distribution point is in fact their 'demarc'. Proper solution is to get telco out there to install a modern demarc with a seperate rj11 for each existing or potential pair on the incoming drop. (Like a small apartment building would have). Not to mention the additional noise a field-installed rj connector is likely to add to the line. Failing that, I would mark, by color, which posts the incoming pairs are attached to, via a weatherproof sticker inside the lid, and simply disconnect them, and tape the bare ends. (There is sometimes a digram in the box- if not, draw one.) I would also include a sign saying VOIP is in use, and to NOT reconnect incoming service without verifying status with the subscriber. The signage is needed if the box is outside the house, because telco will sometimes open a demarc on the wrong house, or open all the demarcs to a particular pedestal or pole connection if it is damaged or has to be switched out. If the box is in the basement or garage, it is still a good idea, since somebody else who doesn't understand the VOIP may let them in the house while you are away. In fact, a note or sign in the box is a good idea even for people with rj11 demarcs, for the same reasons, along with a piece of tape over the incoming feed wires or connectors. You never know if the next guy to open the box will be up to speed on what is going on.
aem sends....
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Excellent advice.
As a local telco tech, my first experience with VOIP was VERY confusing.
With the home disconnected from us at the SNID, I discovered dial tone coming FROM the inside of the home. Huh? It had a strange, foreign telephone number working on it, too. Very weird.
Anyway, this was while reconnecting a customer that found satellite-driven VOIP performance was unacceptable enough that he was giving it up and returning to a POTS land line.
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JR

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housed the the cable TV connections and the telephone distribution. An 8 connector wire enters the house and is hardwired to this distribution center (line in). It is here I was going to break into the system to hook up the VOIP modem RJ11 outputs.
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Be cautious about using the physically smaller RJ11/12 plugs in RJ45 sockets. Sometimes the plugs can screw up the flexible pins/wires in the sockets because the shoulder of the plug doesn't quite fit comfortably. Better to make your patch cords with RJ45's.
As for CAT 5 and Ethernet, you must use CAT 5 for 100 MB Enet; you might get away with short stretches of plain old bell wire for 10MB Enet.
CraigT wrote:

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On Sun, 15 Oct 2006 17:16:39 GMT, Bennett Price

When I started making ethernet cables, I didn't know about the importance of pairs, and just wired them in the obvious way (1&2, 3&4, 5&6, 7&8). These worked OK for 10Mb internet (BTW, it's Mb [megaBITS] not MB [megaBYTES]). Then I upgraded to 100Mb. The connection LEDs came on, but no data was transferred. I needed to put new ends on the cables with 3&6 on one pair.

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So, without running Cat5 wire, a secure WIRELESS network would probably be noticably faster than a wired one running on the old Bell 6-pr, right?
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On Sun, 15 Oct 2006 23:01:36 -0500, Jim Redelfs

Maybe not if the wired network used 10mbps equipment.
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Old Bell 6-wire cable will not make you happy at higher data-rates (i.e. 100Mb) even if you re-crimp the shells properly (1&2, 3&6 twisted) because the old bell wire simply doesn't have the required number of twists per foot to reliably move data at high rates. I am surprised that 10Mb even worked for some folks. Perhaps shorter distances.
Anyway, 11G wireless is certainly an alternative, but again, distances and data rates are tied closely. Even great wireless 11G stuff (54Mbps) tails off in performance as the signal decreases, and at 100 feet or more, you'll probably see LESS datarate than a wired 10Mb pipe in a typical home.
Lastly, in a wired scenerio, the link make activate, but due to poor cabling, the error rate may be high, and the effective performance will be much lower. You'll need to look at error and re-transmit rates to see if you have a good solution.
Mark
Jim Redelfs wrote:

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