sundance-communications.com/forum Forums General General Telephone & Systems Information loop current

I used to have problems with Alltel dialtone. Way back we corrected by putting 600 ohm resisters on both the tip and the ring to bring things down. Haven't done that in years though.
Steph

Been there , and it was also years ago . Makes you wonder why the Provider Tech would leave the Trunk like that ?

I have to agree that over 35ma is where I start to see issue, especially in fax and modem lines.

In the Old days, elector mechanicle Offices had battery to the loop thur a relay with two 200 ohm windings. The office battery was 48 volts. If you have not used ohms law for a while V/R=C.
48V/400ohm=120MA. If you wanted to draw more than 120MA you had to provide your own batterys. This is why none of the standards had a high loop current level. There were two limiting factors for the low loop curent standard. First there had to be enough current to operate the relay. Later there had to be enough currect for the two touch tone osolators in those new fangled touch tone phones. Copper wire is big money out of the bugget. Tel co's used 26AG wire for subs close to the co. In the middle they used 24AG wire. For subs farthest from the co they used 26AG wire that has the least resistance per foot. This not only saved money on copper but gave a more uniform loop curent to the field. Now the Tel Co wants to offer a new service. "DSL". DSL would not work on the longest of the 26AG wire loops. They installed "Pair Gain" equipment at the remote FX locations to offer DSL at the end of those long loops. The end of those long loops were all made of 26AG wire makeing for maximem loop curent.

When I worked for Ma Bell in the 70s as a cable splicer I found a lot of 19ga wire in the rural areas. I have used Sandman's regulators several times with great success. Just my 2 cents.

telman3756497: How about the 12ga toll? Twist and solider only, no connectors allowed on toll cable. That stuff had 130 positive on one side and 130 neg on the other, would knock the crap out of you if you didn't watch it.

As far as the regulator go, they are now going to be in all my bids. If ya can't lick um join um. Think I'll buy some stock in Sandman.

I was on a TDA in Colorado Springs in 1973 with Mountain Bell . I am pretty sure I got bite hard by something like that 130/130 . I know from that time on I wore my leather lacing gloves when soldering on the frame .

Those old carrier systems were really hot. The old open wire toll leads would give ya a good kick too. Those 60 mill teletype circuits would get your attention too. So maybe the high current isn't so new.

Older generations of ISDN BRI cards would put out -190V DC with a healthy (or unhealthy if bitten by it) current supply… New and safer technology replaced those Bridal C &R cards BUT some are still lurking out there.

I remember back when I started in telecomm. Before I KNEW there was any such thing out there with that kind of voltage. I was doing data install in a small insurance office. I was in the process of putting bridge clips onto a 66-block on my little 56 Kb DDS circuit. Unknown to me, right above it on the block was one of those ISDN circuits. Stupid (and still green) me, was using my Leather men to put the clips in… Hard jolt and a brief blackout later I found my Leathermans stuck in the drywall behind where I was working. Getting those bridge clips in after that was like someone with hand-tremors trying to play the operation game! After that ringing voltage has always felt kind-a nice.

:rofl: :rofl: :rofl: :rofl: