Altec GSM SOCKET AL7020S - Manual (Page 23)

AL7020S, AL7024S Designer’s Guide
Doc. No. DG_7024E Altec Electronic AG Seite 23 / 32
3.9 Reset Signal (ON/OFF Signal)
After power is applied to the AL7020S module, the power-on process is initiated,
which lasts about five seconds, after which the module is ready to communicate. After
power-on, the on/off signal is pulled high to the VCC by a 200kΩ resistor. The module
remains active until power is turned off or the power-off process is initiated by
activating the Reset (ON/OFF) signal. The AT interface answers "OK" to the
application, when the reset is complete.
After the AL7020S is turned on, the line should be pulled low for a minimum of 2
seconds to turn it off. The unit can be turned off only if at least 10 seconds have
elapsed since turning it on. To turn the AL7020S on again, the on/off signal should be
pulled low for a minimum of 800 ms.
Figure 3.8 shows the timing diagram for the on/off signal.
Figure 3.8. On/Off Signal Timing Diagram
In Figure 3.8, the following timing requirements apply:
• T1 minimum = 800 ms.
• T2 minimum = 10 seconds.
• T3 minimum = 2 seconds.
3.9.1 Software Reset
It is possible to reset the module by software, which activates an internal reset
generator (see AT Commands Reference Manual).
T1 T2 T3