What the hell's a dip switch?

Today I engaged in what turned out to be an epic journey of trials and tribulations to get a garage door opener remote for my car. My sister and her daughter already have one in each of their cars, so I decided to go get one for myself. The garage door opener motor is a 1992 Raynor; the date is significant. Openers made in 1993 and afterwards have things called optical sensors and dip switches. But I'm getting ahead of myself. * * * * * * So I went to the home supply store where they sold the remote device and found one that appeared to be "universal." In fact, the box the thing came in said "universal" and it appeared to likely be compatible with a 1992 Raynor mechanism. But noooooooooooooooooo. When I got home and opened the box, the instructions said something to the effect that if your opener is older than 1993 you must STOP. It was quite adamant about that. It was in all red caps. And I know ours is a 1992 model year because on the back of it it says 1992. In fact, it says June 1992. So I stopped. The instructions said push the button on the back of the mechanism by the dip switches and hold the button down. There was no button to hold down and there were no dip switches. * * * * * * I packaged the thing back up and returned it to the home supply store where they cheerfully refunded my $$. I then walked back to the area of the store where they sold the remotes and told the sales person my story. He looked a several boxes and said they all had that language about 1993. I'm trying to remember what of significance happened in 1993 and can't think of anything. But it was apparently a big year in garage door openers. He suggested I call the Raynor Garage Door opener company to see if they could help. * * * * * * So I did. When I got home, I found their website, found a local supplier, Norm's Door Service, a garage door company in Ralston. So I called the number and after several Sisyphean trips through a message routing apparatus, got to person named John. After describing all this to John, he suggested I bring one of the working remotes along with me so they can try to match it. I did take one with me and was able to show it to them where Mike, who turned out to be a former MCC student of mine, determined the right frequency by pointing my remote at a small black electronic gizmo on the counter with red and green lights and a couple of switches (they may or may not have been dip switches), found a suitable unit for me out of their archival shelves, checked to make sure the battery was still good, and sent me on my way with instructions: push the Learn button on the back of the opener by the dip switches and then hold down the remote button for three seconds. Sounded simple enough for even me to do it. So I drove home. I'm now thinking maybe I just didn't see the button or the dip switches. I'm also remembering Capt. Piccard being tortured by the Cardassians and looking at four lights has to say there are five lights. * * * * * * I then bundled up and headed into the very cold garage and put up the step ladder to look at the back of the unit. There was no button. I had been told it might be a green button, or a blue button, or a yellow button, or a purple button by various helpful people at Norm's. But no button. There were no dip switches, either. I don't even know what a dip switch is. I could hear Capt. Piccard loudly saying, "There is no button. There are no dipswitches." I called John back, but he had left Norm's Door Service for a short trip somewhere and he would call me back. * * * * * * When he called back, I explained to him that there was no button and nothing that looked like a dip switch. I still don't know what a dip switch is. However, John, who was very helpful suggested I take a photo and email it to him so they could determine how to program my new remote to open this 1992 relic garage door opener we have. So I bundled up again and went out with my digital camera and took a lovely photo of the back of the unit and emailed it to him. It included the model number, the serial number, the date of manufacture. I emailed it to John. I fully expected the worst. However, John came through in a big way. He called me back and asked if there was a box on the plug where the mechanism plugged into the ceiling. And there was. "Is there a squiggly wire coming out of it?" he asked. There was. "That's basically another door opener up there and if you push the large button on the bottom the door will open. "So now," he said, "pry off that large button and there should be a small button inside. Push that and then hold the button on the remote and it should work. If that doesn't work, then repeat the process but instead of holding the remote button down for three seconds, click it once, pause, click it twice, pause, and then click it three times." I did the first option and it worked. I had done it! I had driven about 40 miles, been to the lumberyard twice, been to Norm's once, been out to the garage four times, and gone up and down the stepladder as many times over three hours on this endeavor. I now have a garage door opener in my car! I never did figure out what a dipswitch is.