sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services Outside Plant OSP Construction Repeater cans?

I found this pic on a website I stumbled upon, and wanted to ask if these were always used for "repeaters" or just certain ones?
https://davewhitmore.net/Images/field/SanibelRepeater2.jpg

A creek I regularly visit had one of these by the road, and it has now been removed, cable and all. Presumably by the phone company, since the whole area was recently excavated, and bears orange paint markings.

What is inside these? and what exactly are "repeaters" in the phone sense? (I am a Ham radio operator, and use radio repeaters all the time)

Repeaters are actually small electronic circuit boards that plug into slots within these housings. Typically, they are used to repeat, or extend the range of a T1 circuit. These circuits are limited in distance over a traditional copper path, so repeaters are needed to keep them moving.

Repeaters receive power from the copper T1 span itself allowing the signal to be repeated (amplified) to make it over the next segment of the route.

Outdoor repeater mountings are usually pressurized in order to minimize the risk of moisture entry so as to protect the cards. They are also made with an air/water-tight design so that even with a pressurization failure, they'll continue to operate until the leak can be repaired. The concept of pressurization is fairly evident in the design of these housings, which often appear to have a bell jar design with tightly-fitting sealed covers. You'll often see warning labels on them regarding pressurization since loosening the cover can easily launch it into your head if the pressure isn't released prior to opening!

A typical repeater housing contains between 12 and 24 T1 circuits, although there are ones that are capable of containing more of these cards.

If you saw a route of these removed from service, it is likely due to the fact that these circuits were moved over to newer fiber optic cable routes, where repeaters aren't needed nearly as frequently.

HERE\'S A PIC OF WHAT THEY LOOK LIKE INSIDE

Would T-Span be another name for them? I often see the white Western Electric (I think) T-Spans mounted on utility poles, some up near the cable plant, others within arms reach.

Yes, Hawk. They are one in the same. The white bolted Western Electric ones that you've seen are the ones that Bell companies used until WECO went away. These things can be installed or mounted literally anywhere along a cable route, whether on a wall, pole, atop a pedestal or even in a manhole.

THE WECO ONE IS ON THE RIGHT

...and these types (or similar) are used in low lying areas (like near creeks) to prevent water from penetrating even plain old copper splices.

Even special circuits can be found in these...not just Ts.

The OP's pic does show it labeled as a repeater but odds are it is not pressurized as there is no F flange/fitting showing protruding from the base of the "helmet".

Thanks for the info, guys! Ed, thanks for the link, I've also always wondered what's inside one.
I have also seen the white square ones that Hawk mentioned, in fact, there's one less than half a mile from my house.

Thanks again!
Will

Thanks for the link Ed. I saw a repeater can yesterday in my travels in an area that Ken describes (creek/swampy area) that I'm sure floods once a year. Road is pretty sparcely populated too, so I guess the repeater can was to extended service to the residential customers in the area.

Thanks Ed and Ken! I always enjoy info on COs and outside plant stuff. Having always been an inside vendor, my knowledge of this stuff doesn't hold a candle to yours. Ken, I can understand with some of your background, but Ed, you never cease to amaze me. Haven't you always been "just" a vendor?

The T1 repeater is actually a Regenerator and not an Amplifier. Amplifiers were used in the Analog days and did indeed amplify the attenuated signal. Since the term repeater was used first the term stuck into the Digital Age.

The digital bipolar pulses transmitted are attenuated as they travel down the copper facility due resistance,temperature,gauge,etc. The regenerator examines the attenuated pulse and determines if it has enough amplitude and time duration to have been a legitmate pulse when it was first transmitted. If the answer is yes, a new pulse is generated at the output and in the correct time position. If the answer is no,it passes the suspect pulse to ground as low level noise.

What EV607797 stated about cable pressure is correct. In addition as a side benefit, since the pressurized cable and repeator "cans" are remotely monitored, a leak tells the telco immediatly that a problem has occured.