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 22 of 69
NOTE: The UART input line TXD (rx_uart) of the GM862-QUAD is NOT internally pulled up with a
resistor, so there may be the need to place an external 47K
Ω
pull-up resistor, either the DTR (dtr_uart)
and RTS (rts_uart) input lines are not pulled up internally, so an external pull-up resistor of 47K
Ω
may
be required.
A power source of the internal interface voltage corresponding to the 2.8VCMOS high level is
available at the PWRCTL pin on the connector, whose absolute maximum output current is 10mA.
A maximum of 9 47 K
Ω
pull-up resistors can be connected to the PWRCTL pin, provided no other
devices are connected to it and the pulled-up lines are GM862-QUAD input lines connected to
open collector outputs in order to avoid latch-up problems on the GM862-QUAD.
Care must be taken to avoid latch-up on the GM862-QUAD and the use of this output line to power
electronic devices shall be avoided, especially for devices that generate spikes and noise such as
level translators, digital ICs or microcontrollers, failure in any of these condition can severely
compromise the GM862-QUAD functionality.
NOTE: The input lines working at 2.8VCMOS can be pulled-up with 47K
Ω
resistors that can be
connected directly to the PWRCTL line provided they are connected as in this example.
NO OTHER devices should be powered with the PWRCTL line, otherwise the module functionality may
be compromised.
