Quote
Originally posted by ev607797:
"The system must use single-line analog sets".

This means that upon going off-hook using a Scooby-Doo phone, CO dial tone is received.

The request is that some digit can be dialed to disconnect the station from the CO line and connect the station to intercom dial tone. Note that the word "digit" is used, not flash key, hold button or speed dial key.
You have hit the nail on the head. In my perfect world, I would love to be able to press # or *, rather than the flash hook, to disconnect from the CO line and go to internal dialing and/or features. But there seems to be no such system, at least off the rack without getting into exotic customization.

While I certainly appreciate all the suggestions and help, as the "customer" in this thread, I'm kind of surprised by some of the attitudes that have been expressed. I think it is important to listen carefully to what the customer wants (as ev607797 obviously did) and work towards a solution which addresses the maximum number of those needs as possible. Obviously all needs may not be able to be met, but that doesn't mean the customer was wrong.