Telephone "Loop Lines"
(The things we did to gain some privacy)
Back in the 1970's, when CB radio was running hot and heavy and new voices could be heard on a fairly frequent basis, there were always additions to the local group. Often, once these newcomers became comfortable with the hobby, and accepted into the "gang" on the local home channel, close friendships would often develop and, in the case of those rare female users, a romantic relationship could develop as well. One of the first things that typical CB'ers looked to do when they wanted to take that first step beyond a casual CB-only relationship, and on to something more serious or meaningful, was to meet up either in person or over a more private medium, such as the telephone. But there was a problem. In many cases, the distances between the two people were often further than a "pre-car" teenager could manage on foot or on a bicycle. Opportunities for face-to-face meetings, therefore, were not always readily available. There were similar issues with using the telephone. Because of rampant paranoia of the FCC, and of rival CB'ers who were always looking for information that they could use against their foes, most CB'ers were hesitant to give out their phone number over the air. Those who were foolish enough to do so, were often rewarded by prank calls at any time of the day or night. Most of our parental units did not appreciate this intrusion into their homes, and more than one CB'er I knew was forced off the air by his parents due to problems incurred by the indiscriminate divulging of private information.
Some of us tried to come up with innovative ways to facilitate the exchanging of phone number over the air in a form which would not reveal the actual number to those ever present lurkers and sandbaggers. Several "encryption" codes were developed, but for those codes to work, it required that both the sender and the receiver know the code, and giving the code over the air, was just as risky as giving your number, and pretty much defeats the purpose. One code was developed where a mutually known phone number was used as a "seed key" and numbers were either added or subtracted from that number to come up with the desired number. The problem with this code is that a clever listener could, with time and some logical assumptions, eventually "crack" this code. With only a few phone exchanges available, and with some numbers like "add 9" or "subtract 9" being clear giveaways to what the seed number was, it didn't take long.
So what to do to solve the problem? Well, it turns out that "Ma Bell" did us all a favor. Anyone who's a computer hacker, and long time phone "phreaker" will tell you that the phone company hosts all sorts of test numbers and tricks that you could do to gainaccess to some "undocumented features" of the local phone system. One of those "undocumented features" was known as a "loop line". A loop line is basically a pair of 2 different phone numbers that, when dialed, would connect together. Normally the numbers were consecutive, like XXX-0074 and XXX-0075. Evidently these numbers were created for phone company techs to test the lines without having to bother the central office operators. We stumbled onto these numbers by accident, when one of our group was playing around with his phone. These numbers were just what the doctor ordered for those of us on the radio who wanted to exchange our personal phone numbers. When someone wanted to talk to someone else over the phone and they didn't have their number, they'd give out one half of the loop line and then dial the second. When they connected, the parties could have a normal phone conversation and, of course, exchange their home phone numbers in the relative privacy of the public telephone system. These loop lines went a long way toward helping us develop relationships outside the CB itself. A special thanks goes out to Ma Bell for providing these tools.
In addition to the loop lines, there were also those lines which you could call, and they would always be busy. The strange thing is that several people could call the same number and actually talk to each other between the busy tones. As could be imagined, this was a rather painful way to have a conversation, but one could pick up some interesting tidbits about special phone numbers and other tricks from those "busy number regulars" who made a hobby out of phone phreaking. I guess this was their version of a "CB-like" hobby. I never had much interest in phones though, I much preferred doing my talking over the radio.
In the last 30 years, the phone system has evolved from mechanical switching to completely digital electronic switching and I thought that, along with this evolution, that things like the loop lines would vanish. But evidently they are still in existence, according to some internet searching. They are fewer in number but evidently there is still a need for them.