The MF Q23 D Digit on a Customised MOH

[hakxon]

What is a MF Q23 D digit?

I am using an external MOH connected to my 4400; i want my MOH to be played from the start.

I was reading the External Music guide, it says:

The external music is a series of assemblies purchased externally which are used to broadcast music,customised announcements, etc
They may be used as music on hold or waiting music on a set and in internal applications such as the automated attendant, routing to guide or A.C.D.
A customised announcement may be played from the start (the MF Q23 “D” digit must be entered during the recording and decoded).

the user manual i have doesnot further mention on MF Q23 D digit,
"the MF Q23 “D” digit must be entered during the recording and decoded" where can i get the details on this or how is this done?