User's Manual

Telit GM862-QUAD/-QUAD-PY
Hardware User Guide
1vv0300692, Rev. ISSUE#0, - 04/10/2005
Reproduction forbidden without DAI Telecom written authorization – All Right reserved – Right of modification reserved page 7 of 69
2.2 Turning OFF the GM862-QUAD
The turning off of the device can be done in three ways:
• by software command (see GM862-QUAD Software User Guide)
• by hardware shutdown
• by hardware unconditional shutdown
When the device is shut down by software command or by hardware shutdown, it issues to the
network a detach request that informs the network that the device will not be reachable any more.
The hardware unconditional shutdown does not issue this request and shuts down immediately the
device.
The hardware unconditional shutdown must not be used during normal operation of the device
since it does not detach the device from the network. It shall be kept as an emergency exit
procedure to be done in the rare case that the device gets stucked waiting for some network or SIM
responses.
If device does not respond to a command in the timeout window, retry issuing the command and if
still no response is received a hardware unconditional shutdown shall be issued and then a restart.
2.2.1.1 Hardware shutdown
To turn OFF the GM862-QUAD the pin ON# must be tied low for at least 1 second and then
released.
The same circuitry and timing for the power on shall be used.
The device shuts down after the release of the ON# pin.
TIP: To check if the device has powered off, the hardware line PWRCTL should be monitored. When
PWRCTL goes low, the device has powered off.
2.2.1.2 Hardware Unconditional Reset
To unconditionally turn OFF the GM862-QUAD the pin RESET# must be tied low for at least 200
milliseconds and then released.
The maximum current that can be drained from the ON# pin is 0,15 mA.
A simple circuit to do it is:
RESET#
Unconditional Power OFF
impulse
GND