User`s guide

Front Panel Operation
4-12 Modem 3600
During password entry, the front panel buttons operate as follows:
Pressing NO makes the character at the cursor change to the next
valid password character.
Pressing YES while the cursor is on any of the first three
password characters makes the cursor advance to the next
password character. When the cursor is on the last password
character, pressing YES makes the modem accept the displayed
password.
Pressing TALK/DATA while the cursor is on the first password
character aborts password entry. When the cursor is on any other
character, this button makes the cursor move to the first character.