At 07:56 p.m. 17/07/2009, you wrote:

We’re doing a lot of in building ‘Multi-Dwelling’ installations, most are based on Ethernet, but some buildings it is not cost effective to deploy UTP and the copper is already in place, so DSLAM’s become the best option.

Good luck. At my previous job we gave up on apartments. Where we had our own UTP it was madness. Contractors for the incumbent stole pairs or even sheaths with wild disregard of ownership. The clients have a reluctance to pay and frequently do a runner. Make sure you have a fella called "Big Ted" who is a cross between King Kong and Wurzel Gumidge, wears a tool belt with bloody big side cutters and picks his teeth with a screwdriver. He visits clients frequently and in his limited vocabulary says, "you gonna pay ?". They do. In between client visits, Big Ted "educates" installation contractors on "the rules" about using other folks cables and gives them "First Aid" lessons. Based on my experience with electricity in apartments, and a guy called Ted Grace. He taught me how to be a linesman.

If anyone has any other ideas (apart from Powerline Communications – just not interested).

Well I have powerline that has been working fine since 1977, but it only signals at 1bps and does require a 10KW amplifier injecting at 33KV. Its called ripple control. Turns the street lights on pretty reliably in Wellington. The amp sounds like a locomotive when its running and does rather dim the lights. I use Planet and MicroNet gear in our OB stuff. Its VDSL 1.0 and gives us 20Mbps symmetric for 1KM. We tend to use it point to point and not with big DSLAMs. It works on audio way-lines in stadiums, museums etc, wet string in old buildings and is pretty useful. Its also good in newer buildings where you have over 25 floor to traverse (allow 4 m per floor). We dropped a cable down 25+ floors the other day with a total run of 250m. No issues at all. Both Planet and Micronet make multi-way switches with it, but we don't have that need yet. It just works and has been great for us. We do have some modern powerline stuff and it does work in high rise buildings, but you need to understand how higher (than 50Hz) propagates on the mains network. Its great in corporates where you aren't allowed to run any cables thru the office, but you need to avoid any coils such as found in meters, CTs, etc. so would be crap in a multi-dwelling building. Ripple and DC inject work a treat tho, and reverse signalling at 100 to 300KHz is also very good. Lower freqs go thru transformers fine. LEB used to read meters that way. R