Re: (PM) PM3 and RJ45 with 4 wires?

Robert Boyle (robert@garden.net)
Thu, 12 Feb 1998 01:22:08 -0500

At 11:46 PM 2/11/98 -0600, you wrote:
>On Wed, 11 Feb 1998, Mia's Virtual Post Office wrote:
>
>> So whats the deal? Am I not getting something? Why does the RJ45 Ether
>> cable that ships with the PM3 have only 4 wires instead of 8? Is this
>> all it needs?
>
>Because those are not ethernet cables, they are for the T1's

Tim is right. I didn't think about your question. However my answer is
correct for Ethernet cables, but NOT for the cable(s) that came with your
PM3. Those are clearly T1 cables. The pinout is:

On the back of the PM3 (or any CSU/DSU)

Pair 1&2 RX
-----------
Network Receive (R1)
Network Receive (T1)

Pair 4&5 TX
-----------
Network Transmit (R)
Network Transmit (T)

(Or the other way around dependent on which end you are looking at CPE or
Telco)

Technically, T1 (& 56/64k) lines are supposed to be RJ48C connectors, not
RJ45. I certainly can't tell you what the difference between them is maybe
someone else can explain. Also, a 56k connector has a different pinout. I
know that on the Telco side, the RJ48X jacks short out when you remove the
cable.

-Robert

Robert Boyle - Engineer - Ext 103 - robert@garden.net
Garden Networks: New Jersey's Premier Internet Service Provider
50 Diller Ave. / Newton, NJ 07860 (973)300-9211 8AM-8PM M-F EST
http://www.garden.net Automatic Response: info@garden.net
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