Hi Stuart,
"Can one convert a twisted pair between the CO & the building to T1? Or does this require a new run of cable?"
I'll base my reply on the assumption that you want the telco to administer the T1 and there is no desire on your part to get into the BLEC or CLEC business ;)
The ease of engineering a metallic T1 to any location would depend on a number of variables:
- what type of modulation scheme is used. Does your telco support HDSL? If so, you may not have a problem obtaining T1 service.
If the telco doesn't support HDSL or some other form of xDSL that can do voice channelization, signalling and framing, then you are forced to order a standard metallic T1. In this case, a number of other variables then come into play:
- the nature of the loop, e.g., whether it has load coils on it, which is usually a function of your distance from the CO comes into play. If it's the telco's contention that there is sufficient copper plant in your area to satisfy the types of services you are going to order from them (remember my assumption above, that you are not going to file for carrier status), then getting them to inexpensively remove those load pots could become an arm-wrestling exercise;
- the attenuation (loss), frequency response (fidelity) of the local loop and its noise properties;
- whether all cable sections that make up the overall span meet emissions-related criteria. Telcos abide by rigid rules governing electromagnetic- and radio frequency- interference (EMI/RFI) emissions. And due to the high power spectral density characteristic of the T1 line in the region of 772 KHz, several different measures are used to prevent interference between the two directions of transmission.
Ordinarily, T1 engineering requires that you either use two separate cables or a single multi-pair, "screened" cable. In the case where two cables are used, each cable is dedicated to one direction of transmission (transmit and receive). The second option, where a single screened cable is used, two or more bundles of wire pairs exist within the same sheath separated by foil or some other form of grounded shielding. Both approaches are designed to prevent the emissions of one direction of transmission from spilling over into the other.
[These techniques are recommended for inside plant applications, as well, but standards that address these emission-related considerations are both lacking and vague for inside work. In practice, due to the superior 'electrical balance' of today's cables, single-sheathed Category x cabling has been used widely by many enterprise IT groups in in-building applications without consequence. Which causes one to muse over whether the specifications for outside plant were arrived at at a time when outdoor splicing techniques and the inherent balance of outside plant cables weren't as good as they are today.]
These design measures also help to mitigate the overall level of noise on those cables, providing that directionality is maintained across all services of a particular type. In this case, T1.
"There is some discussion amongst the shareholders about taking control of the communications infrastructure within the builidng (it's a co-op)... Are you aware of any buildings which have done this?"
Certainly. Often this will be sourced to an electrical contractor, or a BLEC, or even to the incumbent telco under a special assembly arrangement. I believe that Verizon actually has a standalone subsidiary that does this for a living.
"You mentioned several situations where WLL has been employed in NYC (e.g. 9/11 disaster recovery). Do you know the mfr of the systems used?"
The one that comes to mind domestically is Harris Communications, but I'd bet that the other large vendors [LU, NT, Siemens, etc.] also have their fingers into this in order to address their international markets' needs.
"We have cable modem service to the building. The cable company has installed cable ducts in all the hallways. Do the laws you quote apply to cable infrastructure? Can we use these ducts to install our own twisted pair if we choose?"
I can't say for sure whether there are any regs on the books from a FCC- or PUC- standpoint covering inside plant ductwork, but there are facilities sharing mandates for outside plant. This would be pertinent only between franchised service providers who have a need to share the other's pole space or conduits. You may want to also check out the "what's new this week" section on the home page of Cole, Raywid & Braverman LLP, which is the site that I pointed you to the other day (and where I believe I saw some mention of conduit sharing in one of those articles).
crblaw.com
Cable franchises are usually granted locally, so this is an item that could conceivably be worked into the initial negotiations (or upon renewal or renogotiation) of the SP's franchise. I think you would need to check with the cableco and/or the local franchising bureau on this one. In any event, if they do allow co-tenancy in those ducts you can rest assured they would charge you recurring fees.
"As for providing wireless VoIP phones: it's a great idea. I need to think a little bit about how to scale it to provide comm services to an entire building. Any ideas?"
I didn't mention wireless VoIP, although, that's a growing option, too. Instead I mentioned Cable Modem VoIP. Take another look at the first diagram in the Vonage link that I sent to you.
vonage.com
Incidentally, see my next post for more on what this voice ASP is doing in the way of local number portability (the ability to change carriers and take your existing number with you).
IP voice over first-mile high speed access lines could become a very exciting aspect of where we go over the next couple of years. There are some potential problems with some of these approaches, however, if elected independently, or by chance, as opposed to obtaining the service under a structured offering with SLA-like guarantees overseen by the PUC.
Quality of service raises its head as one of them, immediately, but if the service provider is doing their homework this concern can be kept to a minimum. Problem is, there are no QoS criteria that they must abide by in a best effort world.
Rate limiting could be another factor. And related to rate limiting, sudden and unexpected price increases for speeds that would be needed to support multiple IP services, which could blindside the end user. I base this concern on some of the price-tiering moves we've seen and discussed here, lately, both for DSL and CM. But if you factor in the removal of your existing telephone line costs (assuming that you do disconnect them), then maybe the increase in cable charges can be justified.
FAC |
