Most Minimal DC Powered Channel Bank Available?

[Birken Vogt]

What is the most minimalistic channel bank available for private T1 to a few radio audio paths? The customer would like to convert some 2 wire and 4 wire analog telco lines to T1 to clean up some of the constant noise and unreliability issues. We would like it to operate off typical site power of +12v or +24v. It looks like a +DC to -48 converter may also be the way to go and that is OK.

E&M would be a plus but not absolutely necessary.

I have been researching on the internet and there are a large number of products that would fit the bill, but cost and capability are all over the place and reliability for radio sites is an unknown quantity. I am wondering if some of you all have a ready answer to this question.

[Bill_G]

Okay. Why T1 rather than IP transport? You can get DSL pretty cheap these days, and the RAD IPMUX can carry four 4W DS0 circuits right out of the box( and some configuration). You'd need two (one for each end). About $2k per box not counting any of the other supporting firewall / internet appliances you might require.

[Birken Vogt]

T1 is already in place and about to be abandoned for its original purpose and the telco takes T1 downtime a lot more seriously than other types of circuits. Plus I like the low latency of a B channel vs IP.

The reason I asked the question regarding T1 is because it is pretty easy to figure out products etc. for IP but T1 stuff is a little more obscure.

[Bill_G]

And becoming a lot more difficult to find. IP stuff is very common now. Might as well go with the flow. The delay isn't that bad. None of my customers notice it.

But, to answer your question - as other agencies get rid of their T1 transports and go towards IP, there are Zhone / TenSR channel banks out there on the market for cheap.

[Bill_G]

Rhino CB24 seems to be the low cost leader on the market at around $1500 each. You have to order the channel cards separately. Four DS0 rj ports per card. Never worked with them, but haven't read any complaints about them either.

[Birken Vogt]

If I was to transport it over IP, would the delay be consistent enough to do simulcast?

[Bill_G]

Overall, yes, but you would need a simulcast controller with long enough bulk delays to compensate for the network propagation delays. 30000uS tends to be the max that most analog simulcast systems using T1 transport can handle, while ip transport typically have delays in the 25-200mS range. I've seen as much as 500mS. For a 900mhz simulcast paging system over ip, Zetron had to build us an SP box that could buffer 2 seconds because the customer network was so busy. But, for a six site VHF simulcast using Harris Intraplex IP controllers over Cambium microwave, we were in control of the network, and got the delays down to 30mS.