
GL865-DUAL V3 Hardware User Guide
1vv0301018 Rev.5 – 2013-08-05
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights Reserved.
Page 6 of 76
Mod. 0805 2011-07 Rev.2
7.2.1.
Transmission line design
................................................................................................... 33
7.2.2.
Transmission line measurements
....................................................................................... 34
7.3.
GSM Antenna - Installation Guidelines
.......................................................................... 36
8.
Logic level specifications
......................................................................................... 37
8.1.
Reset signal
.................................................................................................................. 38
9.
Serial Ports
............................................................................................................ 39
9.1.
MODEM SERIAL PORT
............................................................................................. 39
9.2.
RS232 level translation
................................................................................................. 41
10.
Audio Section Overview
....................................................................................... 43
10.1.
MIC connection
........................................................................................................ 43
10.2.
LINE-IN connection
.................................................................................................. 44
10.3.
EAR connection
........................................................................................................ 46
10.4.
Electrical Characteristics
........................................................................................... 48
10.4.1.
Input Lines
....................................................................................................................... 48
10.4.2.
Output Lines
.................................................................................................................... 49
11.
General Purpose I/O
............................................................................................ 50
11.1.
GPIO Logic levels
..................................................................................................... 51
11.2.
Using a GPIO Pad as INPUT
..................................................................................... 52
11.3.
Using a GPIO Pad as OUTPUT
................................................................................. 52
11.4.
Using the RF Transmission Control GPIO4
................................................................ 52
11.5.
Using the RFTXMON Output GPIO5
........................................................................ 52
11.6.
Using the Alarm Output GPIO6
................................................................................. 53
11.7.
Using the Buzzer Output GPIO7
................................................................................ 53
11.8.
Magnetic Buzzer Concepts
........................................................................................ 54
11.8.1.
Short Description
.............................................................................................................. 54
11.8.2.
Frequency Behavior
.......................................................................................................... 55
11.8.3.
Power Supply Influence
.................................................................................................... 55
11.8.4.
Working Current Influence
................................................................................................ 55
11.9.
STAT LED Indication of network service availability
................................................. 56
11.10.
SIMIN detect function
............................................................................................... 57