User's Manual
Table Of Contents
- GC864 QUAD V2andGC864 DUAL V2Hardware User Guide
- APPLICABILITY TABLE
- 1 Introduction
- 2. Overview
- 3. GC864 Mechanical Dimensions
- 4. GC864-QUAD V2 / GC864-DUAL V2 Module Connections
- 5. Hardware Commands
- 6. Power Supply
- 7. Antenna
- 8. Logic Level Specifications
- 9. Serial Ports
- 10. Audio Section Overview
- 11. General Purpose I/O
- 11.1. GPIO Logic Levels
- 11.2. Using a GPIO Pad as INPUT
- 11.3. Using a GPIO Pad as OUTPUT
- 11.4. Using the RF Transmission Control GPIO4
- 11.5. Using the RFTXMON Output GPIO5
- 11.6. Using the Alarm Output GPIO6
- 11.7. Using the Buzzer Output GPIO7
- 11.8. Magnetic Buzzer Concepts
- 11.9. Using the Temperature Monitor Function
- 11.10. Indication of Network Service Availability
- 11.11. RTC Bypass Out
- 11.12. DAC Converter
- 11.13. ADC Converter
- 12. Assembly the GC864-QUAD V2 / GC864-DUAL V2 on the Board
- 13. Packing System
- 14. Conformity Assessment Issues
GC864 Hardware User Guide
1vv0300874 Rev.0 – 2010-01-25
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved. Page 41 of 64
10. Audio Section Overview
The first Baseband chip was developed for the cellular phones, which needed two
separated amplifiers both in RX and in TX section.
A couple of amplifiers had to be used with internal audio transducers while the other
couple of amplifiers had to be used with external audio transducers.
To distinguish the schematic signals and the Software identifiers, two different
definitions were introduced, with the following meaning:
• internal audio transducers Æ
HS/MT
(from
HandSet
or
MicroTelephone
)
• external audio transducers Æ
HF
(from HandsFree )
Actually the acronyms have not the original importance.
In other words this distinction is not necessary, being the performances between the
two blocks like the same.
Only if the customer needs higher output power to drive the speaker, he needs to
adopt the Aduio2 Section (
HF
) . Otherwise the choice could be done in order to
overcome the PCB design difficulties.
For these reasons we have not changed the
HS
and
HF
acronyms, keeping them in
the Software and on the schematics.
The Base Band Chip of the GC864-QUAD V2 / GC864-DUAL V2Telit Modules maintains
the same architecture.
For more information and suggestions refer to Telit document:
• Audio settings application note , 80000NT10007a
10.1. Selection mode
Only one block can be active at a time, and the activation of the requested audio
path is done via hardware ,by
AXE
line, or via software ,by
AT#CAP
command .
Moreover the
Sidetone
functionality could be implemented by the amplifier fitted
between the transmit path and the receive path, enabled at request in both modes.