The A770 eyebrow expansion panel from Technisonic provides for four
supplementary input switches to interface with the A710, A711, A720 or
A721 which can expand the total number of inputs from 10 to 14. This
panel (when installed) also provides for control of ICS loop and ICS
call functions. Eyebrow expansion panels are normally shipped with two
default overlay legends which are easily changed in the field. A custom
template allows for customers to configure the overlay to comply with
their specific installation requirement.