On hold message during call transfer

Can you tell me if there is a way to play the prospect an “on hold recording” while they wait to be transferred?

This depends on the call transfer methods you are using.

If you use Skype, and you use BroadcastByPhone for outbound calls, then the call transfer is implemented as a conference call since Skype does not offer native call transfer for outbound calls. During the transfer, the current call has to be put on hold, and no audio is available during that time, i.e., no on hold message can be played during that time. The best solution is to inform the person called that the phone is going to be silent during the call transfer and do not hang up.

If you use Skype, and you IVR Studio or Flex PBX for incoming calls, then the call transfer is native Skype call transfer. The person called will hear the phone ring back during call transfer.

If you use modem and analog phone line, then the audio availability depends on your phone company. Some companies play the ring back sound and other companies no audio.