2.8 Accessory Interface
The table explains what kind of pins the phone supplies to the different accessories.
Pins | GND Charge GEN | Power | RX | TX | ACC | RS232 RS232 | Audio | Audio AGND |
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| I/O | OUT | (IN) | (OUT) | ID | RTS CTS | Out | IN |
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
Charger | √ | √ |
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Connector layout
Connector view from base of phone
12 | 1 |
The connector comprises the following pins:
Audio
Audio In, Audio Out and Audio GND:
Audio IN:
Is a single ended input with a maximum sensitivity of 365 mVrms.
Audio OUT:
The single ended output delivers 0.8Vpp into a 1kΩ load.
These two signals are referred to as AGND.
RS232 Interface
5-pin interface: RX, TX, RTS(RFR), CTS and Gen I/O(DTR or DCD):
This is the communication interface to the Data cable
Pin 3 is connected to a general IO pin on the baseband digital chip. The functionality can be assigned on an accessory by accessory basis to be input, output or interrupt.
Charge
The Charge pin represents the positive contact for the charging funtionality.
GND
The Ground pin represents the digital interface and charger return current.
ID
This pin shows the presence of an accessory and is also an analog ID for the accessory. Accessories which provide charger functionality only do not support this pin and their presence is detected with a valid charger voltage.
Power Out
In the
Due to the fact that the ID of the accessory is detected first, the ACC power is not current limited (protected).
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