On Sun, 15 Oct 2006 09:20:48 -0500, Jim Redelfs
wrote:
In article ,
"Mark Harris" wrote:
Note: You may have a RINGER loading issue is using many OLD phones in your
house today. They carry a REN value
Ringer Equivalence Number
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).
When The Big Splittm 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?
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).
If yes,
can I run POTS *AND* ethernet over the same Cat5 4pr?
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.
If yes, what are the
implications to ethernet performance, if any?
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).
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
A 10mbps network is likely to work. Any faster one may not. The
twisting is important.
--
71 days until the winter solstice celebration
Mark Lloyd
http://notstupid.laughingsquid.com
"God was invented by man for a reason, that
reason is no longer applicable."