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TC65 Terminal Hardware Interface Description
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TC65 Terminal_HD_V02.000b
Page 42 of 65
2007-02-19
3.10.6
RTC Backup Supply
The Real Time Clock (RTC) is supplied from a separate voltage inside the TC65T Terminal
which is also active when the GSM module is in POWER-DOWN mode. An alarm function is
provided for activating/deactivating GSM module (activating only to alarm mode).
You can use the BACKUP pin on the 24pole I/O connector to backup the RTC from an
external battery (non-chargeable).
Table 17: RTC signal description
Signal name
Pin
Description
BACKUP 11
External
battery
GND 12
Ground
If no backup battery is connected then a 100uF capacitor supplies the RTC about 6s during
power interruptions.
3.10.7 Power
Supply
The two pins of the power supply at the IO interface connector are directly connected to two
pins of the Western Jack for power supply. This allows supplying the TC65 Terminal by
using the Power connector or via the IO interface connector.
3.10.8 VDD
Supply
The VDD pin at the IO interface connector may be used for supplying external circuit devices
or applications and indicates the following states of the TC65 Terminal:
•
VDD output voltage = 2.9V @ max. 50mA indicates Normal Operation mode or Airplane
mode
•
VDD output voltage = 0V indicates Power Down mode
3.10.9 ON/OFF
Switch
If the ONOFF pin at the IO interface connector is active low. It can be used to switch on or
switch off the TC65 Terminal.
For more information on how to to switch on or switch off the Terminal please refer to the
chapters 3.5.1 and 3.5.3.