User's Manual

Telit GM862-QUAD/-QUAD-PY
Hardware User Guide
1vv0300692, Rev. ISSUE#0, - 04/10/2005
Reproduction forbidden without DAI Telecom written authorization – All Right reserved – Right of modification reserved page 2 of 69
Contents
1 OVERVIEW 4
2 HARDWARE COMMANDS 5
2.1 Turning ON the GM862-QUAD 5
2.2 Turning OFF the GM862-QUAD 7
2.2.1.1 Hardware shutdown 7
2.2.1.2 Hardware Unconditional Reset 7
3 POWER SUPPLY 9
3.1 Power Supply Requirements 9
3.2 General Design Rules 9
3.2.1 Electrical design Guidelines 10
3.2.1.1 + 5V input Source Power Supply Design Guidelines 10
3.2.1.2 + 12V input Source Power Supply Design Guidelines 11
3.2.1.3 Battery Source Power Supply Design Guidelines 12
3.2.1.4 Battery Charge control Circuitry Design Guidelines 12
3.2.2 Thermal Design Guidelines 14
3.2.3 Power Supply PCB layout Guidelines 15
4 SERIAL PORT 17
4.1 RS232 level translation 19
4.2 5V UART level translation 21
5 MICROPHONE 23
5.1 Microphone line Characteristic and requirements 23
5.2 General Design Rules 26
5.3 Microphone Biasing 26
5.3.1 Balanced Microphone biasing 27
5.3.2 Unbalanced Microphone biasing 28
5.4 Microphone buffering 29
5.4.1 Buffered Balanced Mic. 29
5.4.2 Buffered Unbalanced (Single Ended) Mic. 31