Telco Infrastructure, RS-485, Cat 5 cable run

[raddoc]

I have a penthouse XTL 5000 consolette and junction box 800 feet away from the operating position of a MC 3000 deskset.

RS-485 Cat 5 cable is recommended to connect the junction box to the deskset, but my only existing infrastructure is 24AWG cable twisted pair (25 pr cables). It will take an act of Congress to run Cat 5 to the affected locations.

Is it feasible to use the telco cables and 66M punchdown blocks and create the appropiate RJ-45 connections from the punchdown blocks to the junction box on one end, and deskset on the other or are signals too adversely affected?

[mr.syntrx]

If it's really RS-485, you should be fine, depending on the baud rate they use and whether the telco cable is in good electrical condition. If they use a high data rate, you might have issues, but if it's only 9600bps you should be OK.

485 is very robust. I've seen RS-485 employed at 9600bps over runs of a mile or so on really crappy, water damaged underground cable, crossing the paths of power, phone etc, in irrigation systems with no problem.

[SlimBob]

What he said. Twisted pair can generally support quite a bit given the right physical media adaptor and protocols (i.e. HDSL on a HiCap T1). However, RS485 is a multi-master protocol... google it and you'll get some hints on making it work for longer distances...

You may want to make that telco block section as short as possible and hop to CAT5 ASAP. I don't know. If it's really RS485 or RS422 at 9600 bps or slower, you should be good for 4Kft or so

[kj7xe]

I have a penthouse XTL 5000 consolette and junction box 800 feet away from the operating position of a MC 3000 deskset.

RS-485 Cat 5 cable is recommended to connect the junction box to the deskset, but my only existing infrastructure is 24AWG cable twisted pair (25 pr cables). It will take an act of Congress to run Cat 5 to the affected locations.

Is it feasible to use the telco cables and 66M punchdown blocks and create the appropiate RJ-45 connections from the punchdown blocks to the junction box on one end, and deskset on the other or are signals too adversely affected?

We are doing this exact same thing in a building here and it works fine, I believe the longest run is about 400 feet or so. Any loss that's there is not noticeable. It's old 70s-era 25-pair cabling used for a key telephone system that had individual runs from the phone room to each room in the building. I was skeptical at first but then when I realized the data was only 9600bps I went ahead with it. I've tried doing this with Ethernet and it gave me trouble...

[dvpman]

if anything change out the 66 block and use BIX, it's cat5 standard.

M

[raddoc]

Initially did the install with 1 MC3000 console per junction box, one junction box per xtl5000 radio and located both MC3000 800 ft from the junction box. Everything worked fine 800 ft away.

Recently had another telco path made available for another installation location and wired a path (straight through cable equiv) using telco Cat 3. I'm able to make additional MC3000 work from this new location if they are the only consoles plugged into either junction box. I'm able to have the MC3000 consoles work from the original location if they are the only consoles plugged into the junction boxes. However, whenever I plug both RJ45 cables into the Junction box (800ft MC3000+new MC3000) into the same juction box, I get a steady busy light on the junction box (L3208). Desired configuration is radio-junction box < Mc3000 (800 ft)
Mc3000 (400 ft) These are well within the quoted 5k limit.

Any ideas what is triggering a contant busy light whenever the second RJ45 is plugged in? The MC3000 hints that only once should be terminated but fails to describe how to turn off line termination within the console.