LISA-U1 series - System Integration Manual
3G.G2-HW-10002-3
Preliminary
System description
Page 52 of 125
CTS OFF
CTS ON
Active mode is held for 2000 GSM frames (~9.2 s)
time
Wake up time: up to 15.6 ms
time
TxD
module
input
Wake up character
Not recognized by DCE
Figure 25: Wake-up via data reception without further communication
Figure 26 shows the case where in addition to the wake-up character further (valid) characters are sent. The
wake up character wakes-up the DCE. The other characters must be sent after the “wake up time” of 20 ms. If
this condition is satisfied, the characters are recognized by the DCE. The DCE is allowed to re-enter idle-mode
after 2000 GSM frames from the latest data reception.
CTS OFF
CTS ON
Active mode is held for 2000 GSM frames (~9.2s)
after the last data received
time
Wake up time: up to 15.6 ms
time
TxD
module
input
Wake up character
Not recognized by DCE
Valid characters
Recognized by DCE
Figure 26: Wake-up via data reception with further communication
The “wake-up via data reception” feature can’t be disabled.
The “wake-up via data reception” feature can be used in both +UPSV=1 and +UPSV=2 case (when
RTS
line is set to OFF).
In command mode, if HW flow control is not implemented by the DTE, the DTE must always send a
dummy “AT” to the module before each command line: the first character will not be ignored if the
module is in active-mode (i.e. the module will reply “OK”), or it will represent the wake up character if
the module is in idle-mode (i.e. the module won’t reply).
No dummy “AT” is required from the DTE during connected-mode since the module continues to be in
active-mode and doesn’t need to be woken-up. Furthermore in data mode a dummy “AT” would affect
the data communication.