Well, that's strange, I thought their sales support knew what they were talking about.
If you look at what it says in the FEATURE REFERENCE, you will find something like this:
"When the number of waiting calls" = or greater" to
"Calls-in-Queue Alarm Threshold setting" ..........the calling group members can be notified in either of two ways:
Through an external alert connected to an MLX telephone by using a Multi-Function Module (MFM)..."
The fea ref goes on and mentions use only a strobe blah blah blah, but there's a chime that does it interrupted as well.
THAT IS THE ONLY WAY to get an audible, YOU MUST USE AN MFM FROM AN MLX SET PERIOD.
So, now you gotta' get an 008-MLX, 1 MLX Set and 1 MFM and a CHIME, if they really want this.
-OR-
Just put a button on their phone and tell 'em to look at this!
GOOD LUCK!