Bel - 940
RJ25 Pinout
Latest versions of BEL detectors are not using power-supply connector only but 6 pin RJ25. Table below describes pinout of this connector.
| Pin number | Pin functionality |
|---|---|
| 1 | Serial data input |
| 2 | Volume control input. Connecting to ground is the same as pressing the VOLUME button. Short grounding mutes/unmutes the speaker, longer grounding starts volume adjust sequence. Internally connected to +5V via resistor 2.7K. |
| 3 | Ground |
| 4 | Supply (+12V) |
| 5 | Alert output (open collector). Normally connected to ground, floating during alert. |
| 6 | Serial data output (open collector). |
Schematic of the I/O
Glossary:
RJ_n - n RJ connector pin n.
RxD - RxD input of the processor
TxD - TxD output of the processor
MCU_AL_OUT - output of the processor (active during alert)
MCU_SW_VOL - control output of the processor
Author of these pages takes NO RESPONSIBILITY of any damages nor expenses caused by supplied informations.