Integration Manual

LISA-U2 series - System Integration Manual
UBX-13001118 - R25 System description Page 59 of 182
If AT+UPSV=2 is set and HW flow control is disabled, the RTS line is monitored by the module to
manage the power saving configuration:
 When an OFF-to-ON transition occurs on the RTS input line, the UART is enabled and the module
is forced to active mode: after 20 ms from the transition the switch is completed and data can be
received without loss. The module cannot enter idle mode and the UART is kept enabled as long
as the RTS input line is held in the ON state
 If RTS is set to OFF state by the DTE, the UART is immediately disabled (held in low-power mode)
and the module automatically enters idle mode whenever possible
For more details on the power saving configuration controlled by the RTS input line see section 1.9.2.3
and the u-blox AT Commands Manual [2], AT+UPSV command.
DSR signal behavior
If AT&S0 is set, the DSR module output line is set by default to ON state (low level) at UART
initialization and is then always held in the ON state.
If AT&S1 is set, the DSR module output line is set by default to OFF state (high level) at UART
initialization. The DSR line is then set to the OFF state when the module is in command mode or in
online command mode and is set to the ON state when the module is in data mode (see the u-blox AT
Commands Manual [2] for the definition of the interface data mode, command mode and online
command mode).
☞ The above behavior is valid for both Packet-Switched and Circuit-Switched data transfers.
DTR signal behavior
The DTR module input line is set by default to OFF state (high level) at UART initialization. The DTR
line is then held by the module in the OFF state if the line is not activated by the DTE: an active pull-
up is enabled inside the module on the DTR input. Module behavior according to DTR status depends
on the AT command configuration (see the u-blox AT Commands Manual [2], &D AT command).
Except for “01” product version, if AT+UPSV=3 is set, the DTR line is monitored by the module to
manage the power saving configuration:
 When an OFF-to-ON transition occurs on the DTR input line, the UART is enabled and the module
is forced to active mode: after 20 ms from the transition, the switch is completed and data can be
received without loss. The module cannot enter idle mode and the UART is keep enabled as long
as the DTR input line is held in the ON state
 If DTR is set to OFF state by the DTE, the UART is immediately disabled (held in low-power mode)
and the module automatically enters idle mode whenever possible
For more details on the power saving configuration controlled by the DTR input line, see section 1.9.2.3
and the u-blox AT Commands Manual [2], AT+UPSV command.
DCD signal behavior
If AT&C0 is set, the DCD module output line is set by default to ON state (low level) at UART
initialization and is then always held in the ON state.
If AT&C1 is set, the DCD module output line is set by default to OFF state (high level) at UART
initialization. The DCD line is then set by the module in accordance with the carrier detect status: ON
if the carrier is detected, OFF otherwise. For a voice call, DCD is set to ON state when the call is