User's Manual

HiLo3G-850 User Manual
04 March 2011 - Page 20 / 36
Figure 21: Partial V24 connection (2 wires) between HiLo3G-850 and host
As DSR is active (low electrical level) once HiLo3G-850 is switched on, DTR is also active (low electrical level),
therefore AT command AT+Ksleep can switch between the two sleep modes available for HiLo3G-850.
DTR input signal is internally pulled up to VGPIO with a 100KΩ, this result in 28μA of extra consumption
As CTS is active (low electrical level) once HiLo3G-850 is switched on, RTS is also active (low electrical level),
therefore AT command AT+Ksleep can switch between the two sleep modes that are available for HiLo3G-850. The
HiLo3G-850's firmware allows the rise of CTS during the sleep state even when looped to RTS signal.
DCD and RI can stay disconnected and floating when not used. Otherwise use 100KΩ pull up to VGPIO.
Moreover this configuration does not allow the signaling signals as below:
• RI signal used when programmed to indicate an incoming voice or data call or SMS incoming etc…
• DCD signal used to signal the GPRS connections
• DSR signal used to signal the module UART interface is ON
• DTR signal used to prevent the HiLo3G-850 module from entering into sleep mode
3.6 GPIO
There are three GPIOs available on HiLo3G-850. Customer application can directly use them through the appropriate AT
command as:
- Output: pin is set to High or Low state
- Input: pin is read on request and answer is given to the customer application
As input, different cases are possible to cover the maximum possibility of customer application:
• Synchronous answer to the AT command
• Asynchronous answer to the AT command. The customer application prior to the request has configured the GPIO to
react on falling/rising edges. The customer application is notified asynchronously by AT command answer when the
configured trigger occurs.
Figure 22: Programmable GPIO configurations