[c-nsp] DS3 cabling question

[Antonio Querubin]

On Thu, 21 Apr 2005, Rik Koenig wrote:

> I have to cable up a lab to run DS3 between routers. Specifically, there
> will be cable runs of 40-55 feet, between a patch panel and PA-2T3s and
> PA-T3s on 7500s, 6-port DS3 on a 12000, and a couple of Juniper M40s.
>
> The first part of all this is getting cable. I'm pretty new to DS3 and would
> like some assistance. I have seen some companies call for a run of 734/735
> cable, and I've seen used runs of RG179. Is there any difference between the
> types of cables for this application?

As long as the coax cable impedance is 75 ohms and the connectors are 75
ohms you should be ok. The differences in coax will be mainly in
attenuation, shielding, flexibility, and plenum rating.  The factors that
affect the quality of your signal transmission are the first 2 but for the
above runs the attenuation isn't a big factor.  Even cable TV coax (RG-59
or RG-6) is ok as long as you terminate them with 75 ohm BNC connectors.
One thing to watch for though is that if you have to couple 2 short
segments together be sure you use 75 ohm couplers.  Standard BNC couplers
are only 50 ohms.