could you please give me some introductions about the hardwares?
which component is BCU? which is EIB/RS232-Translator? Has Linksys Wlan-router the RS232-Interface?
thanx very much!
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The Linksys WRT54G(S) has no externally accessible RS232 interface. On the electronic board, there is a connector where you can find the Rx and Tx signals of the serial ports, but the electrical levels are 0V / 3V3 (while RS232 is +12V / -12V). With the signals on this connector, it's possible to connect a RS232 interface like the one described at http://www.rwhitby.net/projects/wrt54gs
A BCU is a KNX bus coupling unit. It has a KNX bus connector on one side and a 10 pole connector on the other side called PEI interface (with ground, +5V, Rx, Tx, ...). The BCU contains a microcontroller executing the KNX protocol stack and allowing (among others) serial communication on the PEI interface. With the new version of BCU called BCU2, a new protocol (called FT1.2) has been defined on the PEI interface. This new protocol only uses Rx and Tx (no RTS/CTS), and this allow it to be used with WRT54G serial port (also having only Rx and Tx)
The role of the hardware I built is to adapt the serial signal between 3V3 of the Linksys router and the 5V signal of the BCU2. I used Optocouplers to ensure galvanic separation of the 2 systems, but it has been reported to work with a much simpler interface (simply using 2 resistor to set the BCU in FT1.2 mode and connecting Rx of Linksys to Tx of BCU2 through a resistor and vice-versa)
Hallo
i have seen this picture:
http://linknx.sourceforge.net/files/linknx-wrt54gs.jpg
could you please give me some introductions about the hardwares?
which component is BCU? which is EIB/RS232-Translator? Has Linksys Wlan-router the RS232-Interface?
thanx very much!
Hi,
The Linksys WRT54G(S) has no externally accessible RS232 interface. On the electronic board, there is a connector where you can find the Rx and Tx signals of the serial ports, but the electrical levels are 0V / 3V3 (while RS232 is +12V / -12V). With the signals on this connector, it's possible to connect a RS232 interface like the one described at http://www.rwhitby.net/projects/wrt54gs
A BCU is a KNX bus coupling unit. It has a KNX bus connector on one side and a 10 pole connector on the other side called PEI interface (with ground, +5V, Rx, Tx, ...). The BCU contains a microcontroller executing the KNX protocol stack and allowing (among others) serial communication on the PEI interface. With the new version of BCU called BCU2, a new protocol (called FT1.2) has been defined on the PEI interface. This new protocol only uses Rx and Tx (no RTS/CTS), and this allow it to be used with WRT54G serial port (also having only Rx and Tx)
The role of the hardware I built is to adapt the serial signal between 3V3 of the Linksys router and the 5V signal of the BCU2. I used Optocouplers to ensure galvanic separation of the 2 systems, but it has been reported to work with a much simpler interface (simply using 2 resistor to set the BCU in FT1.2 mode and connecting Rx of Linksys to Tx of BCU2 through a resistor and vice-versa)
Schematic of my hardware can be found here:
http://ouaye.net/linknx/bcu-interface/bcu-uart-interface.png
CON1 is the connector on linksys and CON2 the PEI interface of BCU2
Kind regards,
Jean-François