Modem User Manual

LZT 123 1834 4
3 Abbreviations ....................................................................................... 22
Integrating the Wireless Modem ................................................................. 24
4 Mechanical Description......................................................................... 25
4.1 INTERFACE DESCRIPTION ........................................................................................ 25
4.2 PHYSICAL DIMENSIONS ........................................................................................... 27
5 System Connector Interface.................................................................. 29
5.1 OVERVIEW .............................................................................................................. 29
5.2 DEALING WITH UNUSED PINS................................................................................... 32
5.3 GENERAL ELECTRICAL AND LOGICAL CHARACTERISTICS.......................................... 34
5.3.1 LEVEL SHIFTER INTERFACES.............................................................................. 34
5.3.1.1 COMMON LEVEL SHIFTER INTERFACE ............................................................ 34
5.3.1.2 I2C LEVEL SHIFTER INTERFACE...................................................................... 36
5.4 GROUNDS............................................................................................................... 37
5.4.1 ANALOGUE GROUND (AREF) ............................................................................. 37
5.4.2 COMMON GROUND (GND)................................................................................ 37
5.5 REGULATED POWER SUPPLY INPUT (VCC)................................................................. 38
5.6 VOLTAGE REFERENCE (VREF) ................................................................................... 39
5.6.1 VREF AS AN OUTPUT........................................................................................ 39
5.6.2 VREF AS AN INPUT ........................................................................................... 39
5.7 BATTERY CHARGING INPUT (CHG_IN) ...................................................................... 41
5.7.1 CHARGING PROCESS ........................................................................................ 42
5.7.2 SERIES DIODE................................................................................................... 43
5.7.3 BATTERY SELECTION........................................................................................ 43
5.8 POWERING THE MODULE ON AND OFF (ON/OFF) ..................................................... 47
5.8.1 TURNING THE MODULE ON .............................................................................. 47
5.8.2 TURNING THE MODULE OFF ............................................................................. 48
5.9 ANALOGUE AUDIO .................................................................................................. 50
5.9.1 AUXILIARY AUDIO TO MOBILE STATION (AUXI).................................................. 51
5.9.2 AUXILIARY AUDIO FROM MOBILE STATION (AUXO)............................................ 52
5.9.3 MICROPHONE SIGNALS (MICIP, MICIN) .............................................................. 52
5.9.4 SPEAKER SIGNALS (EARP, EARN) ....................................................................... 53
5.10 PCM DIGITAL AUDIO (SSP) ................................................................................... 53