 4 pin Nokia cellphone special connector at the mobile phone | Pin Number | Pin Name | Direction | Description |
| 1 | GND | --- | |
| 2 | TX | --> | |
| 3 | MBUS | <--> | |
| 4 | RX | <-- | |
| A | Vbat | | |
| B | | | is battery type Li ion 74.5kohm to ground. NiMh 35Kohm to ground. |
| C | BSI | | battery thermistor. 25K to 40K |
| D | Gnd | | |
Source:www.pinouts.ru
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