RJ45 vs. RJ48C ???
D. Mark Durrett
Pardon my ignorance, but can anyone explain to me the difference be-
tween RJ45 and RJ48C connectors. As I understand it, the RJ45 is used
mostly for LAN applications while the RJ48C is the connector used for
DS1 Network demarcation point connections. However, they are both 8-
pins and look terribly similar. In fact, I believe they even inter-
work with each other.
Your comments please ...
Cheers!
Mark
**********************************************************************
D. Mark Durrett Phone: 919-991-9036
NetEdge Systems Inc. FAX: 919-991-9060
P.O. Box 14993 e-mail: Mark_D...@NetEdge.com
R.T.P, NC 27709 web: http://www.netedge.com
**********************************************************************
John Dearing
D. Mark Durrett (mark_d...@netedge.com) wrote:
: Pardon my ignorance, but can anyone explain to me the difference be-
: tween RJ45 and RJ48C connectors. As I understand it, the RJ45 is used
: mostly for LAN applications while the RJ48C is the connector used for
: DS1 Network demarcation point connections. However, they are both 8-
: pins and look terribly similar. In fact, I believe they even inter-
: work with each other.
You are quite correct that the hardware is similar. In fact, it is the
same hardware - 8 pin plugs and jacks.
Unfortunately, what has happened is that almost *any* 8 pin plug or jack
is called "RJ45" nowadays, even when used for non-telephony applications
like LAN wiring.
The RJ45 specified a data jack with the dialtone connected to pins 4,5. In
no other application can an 8 pin plug/jack be correctly called "RJ45",
even though just about everyone does. 8-)
Even the RJ48 series has variations. The RJ48C is the most common demark
for T-1's and is wired on pins 1,2 and 4,5. The RJ48S is commonly used to
demark lower rate circuits (like 64K and under DDS circuits and the like).
It is wired on pins 1,2 and 7,8.
Ethernet 10BaseT LAN wiring uses an 8 pin plug/jack and the signals are
carried on pins 1,2 and 3,6.
In each case, same physical hardware but a different application and
pinout.
John
--
John Dearing : Philadelphia Area Computer Society IBM SIG President
Email : jdea...@netaxs.com
U.S.Snail : 46 Oxford Drive, Langhorne PA 19047 (USA)
Voice Phone : +1.215.757.8803 (after 5pm Eastern)
BLeyton
"D. Mark Durrett" <mark_d...@netedge.com> wrote:
>Pardon my ignorance, but can anyone explain to me the difference be-
>tween RJ45 and RJ48C connectors. As I understand it, the RJ45 is used
>mostly for LAN applications while the RJ48C is the connector used for
>DS1 Network demarcation point connections. However, they are both 8-
>pins and look terribly similar. In fact, I believe they even inter-
>work with each other.
>Your comments please ...
Well, I'm no expert on the subject, just a lowly end-user, but when we
installed a T1 in my last company, I wired everything up using Cat 5 wire
and the same RJ45 connectors that I use for LANs, and everything works
great. Maybe some of the experts in the group can comment on the
electrical characteristics & tell us if there is any physical difference
between RJ45 & RJ48C.
Brian
Jay R. Ashworth
D. Mark Durrett (mark_d...@netedge.com) wrote:
: Pardon my ignorance, but can anyone explain to me the difference be-
: tween RJ45 and RJ48C connectors. As I understand it, the RJ45 is used
: mostly for LAN applications while the RJ48C is the connector used for
: DS1 Network demarcation point connections. However, they are both 8-
: pins and look terribly similar. In fact, I believe they even inter-
: work with each other.
: Your comments please ...
Sure... it's that time of the month again.
RJ-45 and RJ-48 are FCC designations for different ways of hooking
wires up to an 8-position, 8-conductor modular jack.
The jack, alone, carries no RJ- designation, although it is often (I'm
damned tempted to say _always_) misdescribed this way.
Cheers,
-- jra
--
Jay R. Ashworth j...@scfn.thpl.lib.fl.us
Member of the Technical Staff Unsolicited Commercial Emailers Sued
The Suncoast Freenet Pedantry: It's not just a job, it's an adventure.
Tampa Bay, Florida http://members.aol.com/kyop/rhps.html +1 813 790 7592
Peter Macaulay
Jay R. Ashworth wrote:
>
> D. Mark Durrett (mark_d...@netedge.com) wrote:
> : Pardon my ignorance, but can anyone explain to me the difference be-
> : tween RJ45 and RJ48C connectors. As I understand it, the RJ45 is used
> : mostly for LAN applications while the RJ48C is the connector used for
> : DS1 Network demarcation point connections. However, they are both 8-
> : pins and look terribly similar. In fact, I believe they even inter-
> : work with each other.
> wires up to an 8-position, 8-conductor modular jack.
This may provide the additional detail you need. The RJ-45 and
RJ-48 are 8-pin modular jacks. With the popularity of technologies
like Ethernet the term "RJ-45" has become a generic term. In the
past it was a specific configuration.
Here are the common uses of the RJ-48 ...
RJ-48S = 56/64 kbps DSU/CSU 4-wire
1 = Receive Ring
2 = Receive Tip
3
4
5
6
7 = Ring
8 = Tip
RJ-48C = T1 and Fractional T1
1 = Receive Ring
2 = Receive Tip
3
4 = Ring
5 = Tip
6
7
8
Corrections, additions and updates welcome.
------
Peter Macaulay pm...@fox.nstn.ca
Cabling FAQ maintainer.
See ftp://rtfm.mit.edu
Christopher Smith
Just wanted to add one thing, RJ-48C is also I believe called the smartjack.
It is used to terminate T-1s b/c it auto loopbacks. If you don't have a plug
in the jack, the circuit is looped back so that the telco knows that the
circuit is unplugged.
In article <32D22B...@fox.nstn.ca>, pm...@fox.nstn.ca says...
Cliff Liles
Peter Macaulay <pm...@fox.nstn.ca> wrote:
There are also 50 pin versions of the RJ48, namely the RJ48M that
connects 8 T1 lines, and the RJ48H that connects 12 T1 lines on
Amphenol 25 pair connectors.
CL
Cliff Liles
csm...@vtcs.net (Christopher Smith) wrote:
>Just wanted to add one thing, RJ-48C is also I believe called the smartjack.
>It is used to terminate T-1s b/c it auto loopbacks. If you don't have a plug
>in the jack, the circuit is looped back so that the telco knows that the
>circuit is unplugged.
What you are describing is the RJ interface to the "Smart Jack", not
the Smart Jack itself. The RJ48 (for T1) with integral loop
connections is an RJ48X.
Smart Jack is a generic term which is used to describe the DS1 Network
Interface Unit or "DS1 connector" that provides the Telco demark on a
T1 line in most of the country. The NIU is "smart", in that it
responds to a network loop code, and can regenerate the signal in
loopback. (The NIU is typically wired with an RJ48X to the customer,
so that if the cable is removed, the signal is looped back to the
network)
CL