CO line hunting is ALWAYS, repeat ALWAYS a telco feature on traditional copper (POTS) lines. Please always remember this and never let anyone tell you otherwise. A way to remember this is that they charge a monthly fee for this feature in most areas, just like call waiting or caller ID.

It is NEVER a feature that a standard key system can offer; it just simply can't be done, regardless of the manfuacturer of the system or the local telco.

You see, if a line is engaged on a call, the line is just busy, period. Once it's tied up, your system doesn't have any way of knowing about other calls trying to come in. This is because the telco is just telling callers of this through a busy signal. The door is simply locked once the first call is taken on that line unless alternate arrangements are made.

Imagine that the telco central office switch is your receptionist. This person knows you are on the phone. They aren't going to send you another call unless they are told that it's OK to do so. Otherwise, they are going to reject the subsequent callers.

No offense intended if this is too simplistic of an analogy, but it was the best that I could come up with late at night.

If the telco is told to, and paid to do so, they can program their switch to be that "receptionist" and sense that the first line is busy and bounce the next call to another POTS line, A.K.A. an alternate path into your system for the subsequent call, referred to has hunting.

This day and age of telco voice mail service has further complicated this misconception about "lines". People don't understand why if they have a private line and a voice mail system at their location, then can't their voice mail answer subsequent calls on the private line when it's busy? No, it can't because the LINE is busy, not the number. People translate phone numbers as phone lines, and that's not how it works anymore. At least since the 1970's anyway.

A "line" is a pair of wires carrying a single telephone call. When that's happening, that's all that the pair of wires can do. A phone number nowadays is more of a pointing tool; it can be told to select alternate routes to permit more than one call to it at a time.

The use of POTS lines in the United States is still very much the norm, and represents more than 70% of today's typical users. Other technologies are out there that allow more flexibility, but people are under that misconception that they can get them through POTS lines. Some features, yes, but most, NO. POTS lines are good for one call at a time, period. (OK, yes, there is the possibility of call waiting, but for all intensive purposes...)

The hunting feature on the system in your truck has absolutely, positively no way of providing CO line hunting. If it has a hunting feature, rest assured that as previous posts have indicated, this applies for station to station calling, as in intercom calls. I don't even know what system you have but I can make this statement on CO line hunting with 100% confidence.

Sorry that you simply asked for the time and I told you how to build the watch, but this question comes up daily in my office. I just figured that it's about time that I put the answer to this question in writing for my staff to use, and at the same time, maybe others may benefit.

Ed Vaughn, MBSWWYPBX