NGT—Technical description (2011/2012)
126 NGT Transceiver System Technical Service Manual
RS232
IC8 (04-03425) or IC11 (04-03499) provides the interface between the serial port RS232
and the logic levels required by the Application Processor Handset I/F 3 V PCB
(2011)/Application Processor Handset & Data I/F PCB (2012) serial communications
port TXB and RXB.
Real time clock
The transceiver has real time clock capabilities provided by IC10, which is a battery-
backed device to ensure time information is retained during power loss.
Application Processor Handset I/F 3 V PCB (2011)/Application Processor
Handset & Data I/F PCB (2012)
Handset data is fed via the push-pull balanced driver IC6 (drawing 04-03425 or
drawing 04-03499 (sheet 1) and 04-03499 (sheet 2)) on the Audio & Interconnect PCB
(2011)/Audio Interconnect & Data I/O PCB (2012) to channel A of the DUART IC2
(sheet 1) on the Application Processor Handset I/F 3 V PCB (2011)/Application
Processor Handset & Data I/F PCB (2012), where data is decoded for the DSP IC11
(sheet 2).
IC11 is a 32-bit floating point DSP. IC12 and IC13 (sheet 2) are flash memory devices
that hold the main operating code. IC14 and IC15 are SRAM devices.
IC1 is a CPLD used for address decoding, interfacing between various devices and
controlling bus cycle times.
IC16 is another flash memory device that contains all the channel information as well as
the ALE link quality statistics, and user-programmed information such as Address List,
Phone Link List and Control List settings.
Transmit and receive audio is digitally processed by the DSP via the CoDec
(analog/digital audio interface device) IC7. IC7 converts analog audio signals into 16-bit
digital format suitable for the DSP, and converts these digital signals back to analog
format.
Supervisory (Reset) devices IC10 and IC17 monitor the onboard +5 V, +3.3 V and 1.8 V
supplies and reset the system if any of these supplies fall outside the specification.
2011: Drawing 04-03425
2012: Drawings 04-03499 (sheet 1) and 04-03499 (sheet 2)
2011: Drawing 04-03425
2012: Drawings 04-03499 (sheet 1) and 04-03499 (sheet 2)
2011: Drawings 04-03424 (sheet 1) and 04-03424 (sheet 2)
2012: Drawings 04-03498 (sheet 1) and 04-03498 (sheet 2)
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