User's Manual

Note d‘étude / Technical document :
URD1– OTL 5696.1– 003 / 72361 Edition 02
HILO 3G Application Note
17 January 2011 - Page 19 / 38
Figure 18: C
In addition, this signal configuration enabled all signals :
• RI signal used when programmed to indicate an incoming voice or data call or SMS incoming message, etc.
• DCD signal used to signal the GPRS connections
• DSR signal used to signal that the module UART interface is ON
• DTR signal used to prevent the HiLo3G from entering into the sleep mode, switching between Data and AT commands,
hanging up a call or waking up the module etc.
Pull-up resistors of 100KΩ to VGPIO must be connected to DCD, DSR and RI signals.
Avoid supplying the UART before the HiLo3G is ON, this may result in power up sequence error.
3.5.2 Complete V24 Interface with PC
To use theV24 interface, some adaptation of components is necessary to convert the signals from the HiLo3G to +/- 5V
signals compatible with a PC.
Figure 19: Connection to a data cable
PWRON
CTS