Guardian Telecom Inc.
Installation and Operation
DTT-50 & DTT-60 Telephones
Keypad Circuit Board Replacement
•
Remove the main circuit board as described above.
•
Remove and replace the keypad circuit board.
•
Replace the main circuit board and wiring as described above.
LCD Display and Keypad Membrane Replacement
•
The LCD and the keypad membrane are not replaceable in the field. The
telephone must be returned to Guardian Telecom or an authorized
service depot for repair.
Fuses
•
There are no replaceable fuses in the DTT.
•
The phone line fuse on the circuit board of all models is of the resettable
type and is not replaceable. If the fuse trips due to an external event it will
reset in a short period of time. The duration will depend on ambient
temperature and other factors. If the fuse trips repeatedly check the
telephone system wiring.
•
The Ring Detect Relay fuse is a 5 Ampere, fast blow fuse potted on the
circuit board. If the fuse blows the circuit board must be replaced.
Tip: The fuse protects
the Tip and Ring line
from the telephone
system. It is usually
powered at 48 volts DC
and must not be
connected to 120VAC or
230VAC.
Key Functions
While Programming
.............. Hands free mode
.............. Puts phone in programming mode
or
... Scrolls through registers
.............. Returns to main register prompt
.............. Stores number in selected register
.............. Returns to main register without changing contents of selected register
.............. Clears selected register and switches back to main register prompt
While Operating
............. Hands free mode or returns to on-hook
or
... Scrolls through registers in Phone Book mode
or
... Volume control during conversation
.............. Timed disconnect (same as Flash) for some CO or PABX functions
.............. Disconnects from phone line
............. Dials number in buffer
.............. Displays register 0 to 9 for quick dialing
(twice) .. Displays register 00 to 19 for phone book dialing, can scroll with arrow keys
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