A TA-624 wasn't that smart! To the OP, what phones are you using? If they are single line sets, you can program pickup dial to give them the "'9" after a delay of 1 2 or 3 seconds, if I recall. However, if your system is small, it might be time to consider a change, depending on the number of proprietary sets and things like door boxes.

The Emergency dial feature was used to bypass class of service restrictions. You still had to access a line by pressing a line key or dialing 9.

TD and TAW systems frequently show up on Ebay (watch this space :-)) for pennies on the dollar. Then you could replace a 30 year old box with a 20 year old box.

Carl