u-blox LEON-G100 ECALL System Integration Manual Download

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LEON-G100 / LEON-G200 - System Integration Manual

GSM.G1-HW-09002-G3

Preliminary

System description

Page 46 of 125

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 module switches from idle-mode to

active-mode after 20 ms and the module doesn’t enter idle-mode until the

RTS

input line is held in the ON

state



RTS

is set to OFF state by the DTE, the module automatically enters idle-mode whenever possible as in the

AT+UPSV=1 configuration (cyclic idle/active mode)

For more details refer to chapter 1.9.1.3 and

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 and is set to the ON state when the

module is in data mode.

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

u-blox AT Commands Manual

[2], AT&D 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. In case of voice call

DCD

is set to ON state when the call is established. For a data call there are the

following scenarios:



GPRS data communication

: Before activating the PPP protocol (data mode) a dial-up application must

provide the ATD*99***<context_number># to the module: with this command the module switches from
command mode to data mode and can accept PPP packets. The module sets the

DCD

line to the ON state,

then answers with a CONNECT to confirm the ATD*99 command. The

DCD

ON is not related to the context

activation but with the data mode



CSD data call

: To establish a data call the DTE can send the ATD<number> command to the module which

sets an outgoing data call to a remote modem (or another data module). Data can be transparent (non
reliable) or non transparent (with the reliable RLP protocol). When the remote DCE accepts the data call, the
module DCD line is set to ON and the CONNECT <communication baudrate> string is returned by the
module. At this stage the DTE can send characters through the serial line to the data module which sends
them through the network to the remote DCE attached to a remote DTE

RI signal behavior

The

module output line is set by default to the OFF state (high level) at UART initialization. Then, during an

incoming call, the

line is switched from OFF state to ON state with a 4:1 duty cycle and a 5 s period (ON for

1 s, OFF for 4 s, see Figure 26), until the DTE attached to the module sends the ATA string and the module
accepts the incoming data call. The RING string sent by the module (DCE) to the serial port at constant time
intervals is not correlated with the switch of the

line to the ON state.