Quectel UC20 Application Note

UMTS/HSPA Module Series
UC20 PPP Application Note
UC20_PPP_Application_Note Confidential / Released 13 / 29
4.3. Handle URC in Data Mode
Incoming call and short message will not be reported to the port in the data mode during PPP connection.
The level of module’s RI pin will change from high to low for 120ms as indication. MCU can process the
call or short message by switching to command mode according to the status of RI pin. If incoming call or
message exists, the URC will be output to the port when module is changed to command mode.
4.4. Data Carrier Detect (DCD) Function Mode
DCD function mode is determined by AT&C. If AT&C0 was set, the status of DCD pin will not be used to
indicate the data carrier status. And if AT&C1 was set, the DCD pin will be used to indicate the data
carrier status. The pin will hold on low level when data carrier exists or PPP negotiation begins, otherwise
it will keep in high level.
When switching PPP from data mode to command mode (using +++), the DCD state does not change.
NOTE
Quectel
Confidential

Quectel UC20 Specifications

General

Brand	Quectel
Model	UC20
Category	Control Unit
Language	English