Almost two years ago i created a small design with a MAX3232 to make the two UART´s of my Netgear WGT634U available to the outer world. Since the hardware did not work properly imediately i decided to put this strange animal away from the desk. Some days ago i found it and decided to debug it. The design hat a pin swap at the receiver part …
As you can see from the pictures it connects directly to the two pin rows which provide a 3V3 UART signal each. One row you have to assemble on your own. The already assembled one is the debug UART. The MAX3232ECWE converts the both signals to PC RS232 compliant levels. These outputs/inputs are connected to 3.5mm audio connectors so that the PCB fits into the route and you just need to create two wholes into the housing of your router.
Here you can find some pictures of the PCB as well as the layout (pdf format, 1:1) in single positive and double PCB negative format.
Please notice that there is mistake at both receiver paths ! Input and output are swaped for mistake. It is necessary to fix this on the PCB. Since i do not have access to the layout tool anymore i am not able to provide a corrected PCB and the schematic. Please refer to the MAX3232 datasheet to find the necessary assembly and schematic.
C1, C2, C4 and C4 at the MAX3232 are 470nF ceramic capacitors. Do not use tantalum caps. At least it did not work at my side. The capacitor in the power supply of the MAX3232 is a 10uF ceramic type. Here also a tantalum cap might work. Also take care that the ground of the MAX3232 power supply has to be connected to the rest of the ground by wire.
Notice that i do not take reponsibility to possible harm that might be caused to you and your hardware if you use this design !
Find the layout files here:
Single board, positive layout …
Double board, negative layout …