As mentioned in my last blog post, I've also been looking at the panasonic DPT ("Digital Proprietary Telephone", also known as the "Digital Super Hybrid System")
This is a digital signalling format, with a lot of similarities to an ISDN BRI.
Audio is transmitted as G.711 (u-law or …
For quite some time, I've been reverse engineering the Panasonic APT ("Analog Proprietary Telephone", also known as the "Advanced Hybrid System") protocol.
This is a protocol for carrying button press information from phones, and also for carrying status information (LED controls and text to be displayed on an LCD …
The USR302 is a very inexpensive Ethernet to RS485 bridge (with the USR301 being an Ethernet to RS232 bridge).
I bought a few, mostly intending to use them for connecting various MODBUS networks to Ethernet, but looking at the design there's some good potential for modification and customisation.
This …