atcomsystems.ca/forum Forums Other TDM Phone Systems Other Telephones & Systems ....Digital vs ...um Digital

.....anyone mind answering a few questions?
How can you physically note the difference between the eOn 2 wire digital phones and the eOn 4wire digital phones?
What is the differences between the 2 and 4 wire digital phones?
Also, what are the operating differences between the two.

.....I have a new office with eOn phones which have two digital phones per circuit. I know polarity plays a major roll on these phones. ANy info here would be great, I'm digging in to learn all I can on these phones, but its always nice to get the point blank, this is whats goin on from someone else.

duh.. whats eOn stand for

eOn is formerly known as Cortelco, formerly known as ITT, formerly known as Kellogg.

PoE is refering to their Millennium ISDN PBX and its choice of telephone instruments. '4-wire' refers to their legacy ISDN telephones (s-interface). '2-wire' is a newer design (u-interface ISDN) telephone.

If you have the choice, definately go with the 2-wire phones.

The 4-wire ISDN/BRI line card has 16 'logical' ports, but only 8 physical s-loops on the card. Each S-Loop supports two phones, so the phones have a TEI switch on the bottom to identify which logical port to the switch (either the odd/even numbered). Polarity of the wiring must be the same for both phones on the s-loop.

The 2-wire phones operate on the 2-wire DLC, a completely different card than the ISDN/BRI line card. The phones boot much quicker and are by far more reliable than the 4-wire. Polarity is not an issue, and no TEI switches to worry about.

The 2-wire phones also can be run further from the switch than the 4-wire. I forget the distance limit, but its far.

I put in a Millennium pbx with over 200 2-wire phones in a steel mill with all kinds of crap for cabling. Every single phone came up without a problem.

The 4-wire phones may seem like a pain, but they will operate fine if your installation is clean and well managed. I have much more information on the 4-wire phones if you are having specific problems with your switch.

"How can you physically note the difference between the eOn 2 wire digital phones and the eOn 4wire digital phones? "

The part numbers are different, but the easiest way to tell is look at the bottom of the phone...

The 4-wire has a double dipswitch for the TEI and terminating resistor.

The 2-wire phone has a single switch for local or line power.