Vodavi Starplus Triad-S Product Description Manual page 200

Off-Hook Voice Over (OHVO)
Placing an Off-Hook Voice Over Call
When an OHVO station calls a busy OHVO station and a busy tone is
received, the calling OHVO station performs one of the following steps:
Dial the OHVO code [628] on the dial pad,
-or-
Press a pre-programmed OHVO button to initiate an OHVO
announcement, and the following occurs:
Responding to an Off-Hook Voice Over
After receiving an OHVO announcement, three options are available to
respond to the caller:
Option 1 -- This method lets the receiving station respond to an OHVO
announcement utilizing the MUTE feature button. This button is pressed
to carry on a two-way conversation with the OHVO initiator while still
listening to the original call.
Option 2 -- The OHVO receiving station may respond to the calling
station by using the Silent Text Messaging (this feature is only available
to digital key telephones, and the calling station must be a digital display
telephone.)
The HOLD button LED flashes at the called OHVO station.
The OHVO receiving station receives a one-beep warning tone. The
station receiving the OHVO call must be off-hook and in H mode,
then the calling OHVO party may begin the voice announcement to
the called OHVO party. The called OHVO station's existing
conversation is uninterrupted and the voice over announcement
does not drown out the existing conversation.
The calling OHVO station is not connected or able to hear the called
station' s conversation (the connection only allows the calling station
to transmit to the called station).
The calling station is placedina one-time DND mode upon initiating
the Voice Over. One-Time DND cannot be toggled during the OHVO
call. The station receiving the OHVO call must be off-hook and in H
mode.
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