Panasonic KX-TD500 System Reference Manual page 18

Resource cards
Direct Inward System Access (DISA) Card;
This card interfaces 4 central office trunks
arranged for Direct Inward System Access
(DISA) and the TDM bus.
Automatic Gain Control (AGC) Card;
This card is used to maintain volume of CO-CO
communication.
An electronic circuit which compares the level of
an incoming signal with a previously defined
standard and automatically amplifies or
attenuates that signal so it arrives at its
destination at the correct level.
Remote Circuit (RMT) Card;
This card is necessary for accessing the system
from a remote location.
Other cards
Doorphone Circuit (DPH) Card;
This card interfaces 4 doorphones and the TDM
bus. Up to 4 doorphones can be connected to
the system.
Time Switch Conference Expansion Card (TSW
Conference) Card;
This card provides 64 additional conference
trunks, and is installed on the TSW card.
Off Hook Call Announcement (OHCA) Card;
This card is for Off Hook Call Announcement
features, and is installed on the HLC card or PLC
card.
Off Hook Call Announcement for Digital
Telephone (DOHCA) Card;
This card is for Off Hook Call Announcement
features on DPITS, and is installed on the TSW
card.
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