User's Manual

GL865-DUAL/QUAD V3 Hardware User Guide
1vv0301018 Rev.7 – 2013-10-30
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights
Reserved. Page 6 of 78
Mod. 0805 2011-07 Rev.2
7.2.1. Transmission line design ............................................ 32
7.2.2. Transmission line measurements ....................................... 33
7.3. GSM Antenna - Installation Guidelines ................................ 35
8. Logic level specifications ............................................ 36
8.1. Reset signal .................................................. 37
9. Serial Ports ..................................................... 38
9.1. MODEM SERIAL PORT ......................................... 38
9.2. RS232 level translation ........................................... 40
10. Audio Section Overview ........................................... 42
10.1. MIC connection .............................................. 42
10.2. LINE-IN connection ........................................... 43
10.3. EAR connection .............................................. 45
10.4. Electrical Characteristics ........................................ 47
10.4.1. Input Lines ..................................................... 47
10.4.2. Output Lines .................................................... 48
11. General Purpose I/O ............................................. 49
11.1. GPIO Logic levels ............................................ 50
11.2. Using a GPIO Pad as INPUT ..................................... 51
11.3. Using a GPIO Pad as OUTPUT .................................... 51
11.4. Using the RF Transmission Control GPIO4 ............................ 51
11.5. Using the RFTXMON Output GPIO5 ................................ 51
11.6. Using the Alarm Output GPIO6 .................................... 52
11.7. Using the Buzzer Output GPIO7 ................................... 52
11.8. Magnetic Buzzer Concepts ....................................... 53
11.8.1. Short Description ................................................. 53
11.8.2. Frequency Behavior ............................................... 54
11.8.3. Power Supply Influence ............................................ 54
11.8.4. Working Current Influence .......................................... 54
11.9. STAT LED Indication of network service availability ..................... 55
11.10. SIMIN detect function .......................................... 56
11.11. RTC Bypass out .............................................. 56