AT&T MERLIN LEGEND Release 3.0 Programming Summary Manual page 434

Programming Special Characters
Single-Line Telephones
Some dialing sequences need special characters. For example, you would
press and release either the Recall or Flash button or the switchhook to
insert a pause in a dialing sequence after a dial-out code to allow the
system to seize an outside line before dialing the number.
Table H-1. Special Characters for Single-Line Telephones
Press... Means...
Recall, Flash
or switchhook Multiple consecutive pauses are allowed.
#
sequence or to separate group digits, for example, account
H-2 Programming Summary
Pause. Inserts 1.5 second pause in the dialing sequence.
End of Dialing. Used to signal the end of the dialing
code from number dialed.