pciaccio Wed, 03/14/2007 - 03:25

No, E-1 lines are the European Digital Standard level 1 lines. They are 2.048Mhz in speed. It is the media type that you speak about when you say E-1. The protocols that you run on an E-1 (as well as a T-1) can vary. ISDN, Frame Relay, HDLC, PPP, ATM, SMDS, etc, can all run on an E-1. The E-1 is Europes equivilant to the US T-1. The E-3 to the T-3. Hope I answered your question....Good Luck...

a.whiting Wed, 03/14/2007 - 06:21

Hi Carl,

FWIW I've terminated a number of BT(UK) E1 lines as point-to-point 2Mbits/s bearers, using X.21 converters on the end of the 75 Ohm coaxes presented by BT, thence CAB-X21-MT cables to Sync interfaces on routers (in both bridging and routing scenarios). The trick with E1's is in the framing i.e. they present as ITU-T G.703 bearers but you can also order "fractional" E1 using G.704 framing to distribute the timeslots - thus acting as an ISDN PRI cct.

HTH, Andy.

carl_townshend Wed, 03/14/2007 - 08:17

so what do people normally order these as, If I want a point to point circuit would I just order a unchannelized 2 mbits circuit ?

spremkumar Wed, 03/14/2007 - 23:29

Hi Carl

if you want a simple point to point circuit then go ahead for a channelized 2 Mbps circuit..


a.whiting Thu, 03/15/2007 - 02:35

Hi Carl,

Yes - sort of! Order a simple G.703 2Mbits/s(un-channelised) E1 if all you need is a 2Mbits/s point-to-point cct; else order same but with G.704 (channelised) framing if you want to use the timeslots. The presentation is either on unbalanced 75 Ohm BNC coaxes (Tx & Rx legs) or on balanced 120 Ohm twisted-pair RJ-45; the NTU's usually have both. I've attached a couple of .pdf's which may be of use.

Regards, Andy.


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