AT Commands Reference Manual - wireless netcontrol GmbH

Modem Configuration and Profile
Sleep Mode H/W Signals
Two HW lines are used:
• One for waking the H24 (Wakeup-In).
• One for waking the terminal (Wakeup-Out).
Terminal Does Not Wake the H24 (If the Terminal Uses Hardware Flow
Control Only)
When the H24 is in Sleep mode, the CTS line is also inactive. The terminal does not send any
characters to the H24 if the CTS is inactive, otherwise the character may be lost (Hardware Flow
Control).
Terminal Wakes the H24 Using the Wakeup-In Line
The terminal uses the Wakeup-In line (pin #16) to wake up the H24 when it wants to send data.
When the Wakeup-In line is low, the H24 will not enter the Sleep mode. If the terminal has data to
send while the H24 is sleeping, it activates the line (brings it to active low), then waits 30 ms (the
time required to wake the H24). Only then can the terminal start sending data.
Data transmit
TXD
Line (pin #21)
WAKEUP-IN
Line (pin #16)
Idle
Wakeup
30 ms
Figure 3-2: Wakeup-In Line
Two modes exist:
• Idle Mode: The terminal has no data to send. If the terminal enables sleep mode (using
ats24), the H24 activates its Sleep mode module.
• Wakeup Mode: The H24 does not enter sleep mode, and the terminal can send data.
Once the terminal changes the line edge to Wakeup mode, it needs a 30 ms delay before sending
any data to the H24 (using the RS232 protocol).
H24 Wakes the Terminal
• The H24 follows these steps in order to wake up the terminal:
• The H24 indicates to the terminal that it has data and that it must wake up. The H24 uses the
Wakeup-Out Line (pin #26) (brings it to active low).
• While the Wakeup Out line is low, the terminal should not enter Sleep mode.
• The terminal should set a value of the delay (in ms) needed for waking it (using the ATS102
command) before receiving data (default value is 30 ms).
3-252 H24 - AT Commands Reference Manual April 15, 2010