2. ELECTRICAL DESCRIPTION
Data Terminal Ready (DTR)
DTR indicates that the DTE is ready to transmit and receive data. It also acts as a hardware
The DTR line can also be used to switch on the modem when activated for 0.2 seconds. The DTR line must be deactivated prior to switching off the modem to ensure it switches off (powers down) correctly.
Data Set Ready (DSR)
An active DSR signal is sent from the modem to the application (DTE) to confirm that a communications path has been established. DSR has two modes of operation, settable using the AT command AT&S.
Data Carrier Detect (DCD)
DCD indicates that the DCE is receiving a valid carrier (data signal) when low. You can define the exact behaviour of DCD with an AT command.
Ring Indicator (RI)
RI indicates that a ringing signal is being received by the DCE when low. You can define the exact behaviour or RI with an AT command.
2.6 Real Time Clock
The GM29 contains a real time clock (RTC) to maintain accurate timekeeping and to enable “timestamping” of messages.
The RTC is powered when d.c. power is connected to the modem AND the modem is switched on. If the d.c. supply fails, a stored energy device within the GM29 provides
2.7 Software Updates
It is possible and sometimes necessary to update the GM29 software. Updates must be carried out by a Sony Ericsson approved technician. Please contact your supplier for details (see “Service and Support”, page 9).
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