The Tactical Operations Center (TOC) was where, among other things, all the battalion communications were connected. Both radio and telephone (land line) shared the same cramped space. When I was in the operations center and I needed to talk to one of our orderly rooms or to brigade, my phone was right next to the switchboard where I could keep and eye on the operator. That would be the only connection that I could count on keeping without constant vigilance against the fastidious switch board operator who would keep busy by plugging into your line to ask, "Are you working?" meaning, "Is this line being used?"
The Army's mobile telephone system was rugged and, in its basic form, was very reliable. The most basic hookup was two battery powered phones with crank handle ringer, connected by a pair of wires. Turn the crank on one phone and they'd both ring. Add another phone and they'd all ring. Connect the phones to a switchboard, and you could select to whom you wish to speak. For the phones that were connected directly to the same switchboard, it worked well. The problems started when the number of switchboards (and operators) increased.
The switchboard was a box with a bunch of terminal units, each the size of an audio cassette case, plugged into it from the front. Each phone on the exchange was connected by a pair of wires to its own terminal unit. Phone lines from other exchanges had their own terminal too. The boxes could handle about a dozen phones and the boxes could be stacked to increase the size of the exchange. On the face of the terminal unit was a little glass porthole, a 1/4" diameter socket for a headset plug, and a plug on a self retracting wire that could be plugged into another terminal. An incoming call would ring at the switchboard and a white flag appeared in the normally dark port hole of the terminal to show which line was ringing. The operator would then plug his headset into that terminal and identify the exchange. The caller would make his request and the operator would say "Roger" and take the plug from that terminal and plug it into the terminal of their choice, crank the ringer handle, and then unplug his headset. When both phones would hang up, the white flag in the port hole dropped down. The operator would plug his headset into the connection and listen for a few seconds. If he heard nothing he would ask "Are you working?" If there was no answer, he would pull the plug.
Problem was that not all the telephones were connected by wires. We were stationed on ships in the river some of the time. The link to the shore or to the other boats was by single-side-band radio. If the radio was allowed to drift a little off the frequency, voices would sound like something from a bad Sci-Fi flick. (CB radio fans call single-side-band users "hog callers".) A radio link was iffy at best and quite often not even available. Sometimes the connection would just fade away or the white flag on the terminal would drop even if the line was still active. A call to someone in Siagon from aboard the USS Colleton could include three or four radio links along the way, each with their own form of signal degradation, and each with someone ready to pull the plug on you.
The exchange at Division Headquarters was named Reliable, from the Old Reliables moniker for the 9th Infantry. All the telephone exchanges in the division had names starting with the letter R. Our (4/47th) exchange was named Rattle. Second Brigade was Raider. I don't remember any of the others but there was probably a Raccoon or a Revolver in there somewhere. To contact someone through a number of switchboards required you to known the names of the exchanges in advance. Anyone with a speech impediment for the letter R was in trouble. It was more like a verbal internet URL, than it was like dialing a phone number.
If I wanted to call Division operations, for example, I would pick up the phone, crank the handle and wait for the operator to say "Rattle." Then I'd say, "Rattle give me Raider," and he'd say "Roger" and connect me to brigade. (All battalion telephone traffic went through brigade when we were station on the ships) "Raider," a voice on the line would proclaim. "Raider give me Reliable", "Roger". "Reliable!" "Reliable give me G2", "Roger"! (Who is this Roger guy and why does his name keep popping up?) If everything worked right, a phone at Division operations would ring and I could converse with them, most often at the "Sound off like you've got a pair" volume level. If, however, the conversation had to be put on hold, the party that was holding had to maintain the connection by talking, singing or whistling, so that if a switchboard operator plugged in, he could tell that the line was busy and not ask "Are you working?" Failure to say "Working!" fast enough would send you back to the starting line.
I worked the switchboard sometimes just for something to do. It wasn't my job but it wasn't hard, and it beat having nothing to do. Sometimes boredom could even make sitting in front of a box filled with phone wires look interesting. Micro processors do the job now, and they never ask "Are you working?"