Loading...
After Sales Technical Documentation
HF JUNCTION BOX
HFJ±2
Original, 05/94 |
NMP Part No. 0275008 |
HF Junction Box HFJ±2 |
After Sales |
Technical Documentation
AMENDMENT RECORD SHEET
Amendment |
Date |
Inserted By |
Comments |
Number |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Page 2 |
Original, 05/94 |
After Sales |
HF Junction Box HFJ±2 |
Technical Documentation
HF JUNCTION BOX HFJ±2
CONTENTS
|
Page No |
Introduction |
5 |
General |
5 |
Main Features |
5 |
Accessories Supply Voltage |
5 |
Audio Switches |
5 |
Handsfree Audio Amplifiers |
5 |
Charger |
5 |
External I/O |
5 |
Booster Interface |
5 |
Modes of Operation |
5 |
Power±off Mode |
5 |
Power±down Mode |
6 |
Power±on Mode |
6 |
External Signals and Connections |
6 |
Power Supply Connector X210 |
6 |
External Microphone X230 |
6 |
External Speaker X250 |
6 |
Accessory Connector X170 |
7 |
Phone Connector X290 |
7 |
Functional Description |
8 |
Circuit Description |
8 |
Control Block |
8 |
Booster Interface |
8 |
Charger |
9 |
Audio Switches |
10 |
External I/O |
11 |
Power Supply |
11 |
Microphone Amplifier |
12 |
Speaker Amplifier |
12 |
Parts List |
15 |
Original, 05/94 |
Page 3 |
HF Junction Box HFJ±2 |
After Sales |
Technical Documentation
Assembly Parts |
22 |
List of Figures
Figure 1: Block Diagram |
13 |
Figure 2: Component Layout Diagram |
14 |
Figure 3: Exploded View |
22 |
Figure 4: Circuit Diagram |
NO TAG |
Page 4 |
Original, 05/94 |
After Sales |
HF Junction Box HFJ±2 |
Technical Documentation
Introduction
General
The HFJ±2 Handsfree Junction Box provides and controls the supply voltages for the accessories rge current for the phone. In addition, it controls the audio paths to the accessories and handsfree equipment.
The unit contains a protection circuit against battery voltage transients, power switch, handsfree speaker and microphone amplifiers, audio switches, external I/O, switch mode charger and a microprocessor which communicates with the phone via the mbus interface.
The BABT approved version of HFJ±2 is known as HFJ±2X. Since both units are technically identical, all references to HFJ±2 equally apply to HFJ±2X.
Main Features
Accessories Supply Voltage
Filtered and switched voltages are supplied to peripheral devices and to handsfree audio parts in the HFJ±2 box. Protection against disturbances, such as overvoltages, transients in incoming battery voltage, is provided.
Audio Switches
Controls audio paths between phone, handsfree equipment and accessories.
Handsfree Audio Amplifiers
External microphone and speaker amplifiers for handsfree operation.
Charger
Provides supply voltage and charge current for phone.
External I/O
Open collector output, capable of driving an external relay.
Booster Interface
When requested via mbus message, HFJ±2 can read booster tuning values from booster EEPROM and send them to the phone. Tuning values can also be written to booster EEPROM.
Modes of Operation
Power±off Mode
The battery voltage is always connected to the accessory and charger power switches. The rest of the circuitry does not receive supply voltages.
Original, 05/94 |
Page 5 |
HF Junction Box HFJ±2 |
After Sales |
Technical Documentation
Power±down Mode
+5 V supply voltages are switched on. The processor is in power down mode and its clock oscillator is not running.
Power±on Mode
The processor is executing code. +5 V supply voltages are on and other supply voltages are under processor control.
External Signals and Connections
The module is provided with five external connectors: power supply connector, external microphone connector, external speaker connector, phone connector, and accessory connector.
Power Supply Connector X210
Pin |
Name |
Description |
|
|
|
1 |
XCRM |
External car radio mute: open collector output is pulled down- |
|
|
when radio is muted, when radio is not muted, collector output |
|
|
is in a high impedance state. The load relay should be con- |
|
|
nected between this pin (1) and +Vbat. |
|
|
± on state max. voltage: +1 V |
|
|
± on state max. current: 250 mA |
|
|
± off state max. current: 1 mA |
|
|
± load resistance min.: 64 Ω |
|
|
|
2 |
IGNS |
Input controlling auto power off function: should be connected |
|
|
to car ignition switch (after switch) when in use and to ground |
|
|
when not in use. |
|
|
|
3 |
GND |
Power supply ground: should be connected to car battery neg- |
|
|
ative terminal. |
|
|
|
4 |
+VBAT |
Power supply voltage: should be connected to car battery posi- |
|
|
tive terminal. |
|
|
|
External Microphone X230 |
||
|
|
|
Pin |
Name |
Description |
|
|
|
1 |
GND |
Ground for external microphone. |
|
|
|
2 |
HFMIC |
Supply voltage for microphone / audio signal from microphone. |
|
|
|
External Speaker X250 |
||
|
|
|
Pin |
Name |
Description |
|
|
|
1 |
GND |
Ground for external speaker. |
|
|
|
2 |
HFSP |
Audio signal (d.c.) to speaker/speaker indication. |
|
|
|
Page 6 |
Original, 05/94 |
After Sales |
HF Junction Box HFJ±2 |
Technical Documentation
Accessory Connector X170
Pin |
Name |
Description |
|
|
|
1 |
+VBS |
Power supply for accessories; HFJ±2 turns this voltage on and |
|
|
off under phone control. |
|
|
|
2 |
DGND |
Digital Ground. |
|
|
|
3 |
M2BUS |
Serial mbus data between handset, HFJ±2 and accessories. |
|
|
|
4 |
LSP |
Not Connected. |
|
|
|
5 |
PWR |
This signal is pulled to +5 V at HFJ±2 via an internal resistor. |
|
|
Indicates external handset power±on switch state to HFJ±2. |
|
|
|
6 |
AGND |
Analog Ground. |
|
|
|
7 |
MIC |
Audio signal from accessories to phone (transmitted audio) or |
|
|
HF speaker (voice dialer phrase, answer machine message). |
|
|
|
8 |
EAR |
Audio signal from phone (received audio) or from HF micro- |
|
|
phone to accessories. |
|
|
|
Phone Connector X290 |
||
|
|
|
Pin |
Name |
Description |
|
|
|
1 |
SCL/TXI |
IIC bus clock for booster; this signal is pulled to +5 V at HFJ±2 |
|
|
via the internal resistor of the processor. This pin is also used |
|
|
for booster error indication; in error condition, the booster pulls |
|
|
this pin (1) down (pin 1 can be used as an output to the boost- |
|
|
er at the same time). Periodically, Pin 1 is changed to input for |
|
|
60 s time and TXI state is polled. These polling pulses must |
|
|
be filtered in the booster. |
|
|
|
2 |
PGND |
Ground for charger. |
|
|
|
3 |
M2BUS |
Serial mbus data between phone, HFJ±2 and accessories. |
|
|
|
4 |
VC |
Supply voltage/charging current for phone. |
|
|
|
5 |
HOOD/SDA |
Handset hook ind./IIC bus data for booster. |
|
|
|
6 |
SGND |
Signal ground. |
|
|
|
7 |
XMIC/ |
Audio signal from accessories or HF microphone to phone: |
|
JCONN |
100 kΩ pull±up to +5 V; d.c. level indicates connection of |
|
|
HFJ±2 box to phone. |
|
|
|
8 |
XEAR/ |
Audio signal from phone (received audio) to accessories or HF |
|
HFJPWR |
speaker: 1 MΩ pull±up resistor to +VBAT, drop down of current |
|
|
from this pin turns on +5 V supply to the processor. |
|
|
|
Original, 05/94 |
Page 7 |
Loading...