User manual

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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 for RI with an AT command.