I built an HdX PCB to modify an RS232, Fred Kaal design, (http://members.ziggo...kaal/index.html)
and now I´m ready to mount it in the original RS232 but have some doubts regarding the installations of the switchs and would like to check if somebody already did it and can help me.
1) According to the schematic view (http://members.ziggo...232_dsr_ram.gif) the trace that has to be cutted is the one that goes from pin 8 of the 74LS21 (u17) to pin 1 of the 74LS125 (u6), but in the picture of the modifier RS232 card (http://members.ziggo...card_rs232.html) the trace that is cutted is pin #3 of the 74LS125 (u6).
2) Switch 1 (SW1) is added to be able to close the previous cutted trace and also pin #1 of the 74LS125 (u6) is connected with a 10K Resistance (R6) to +5V, is that correct? Any suggestion on where to take those +5V? Could pin12/13 of the 74LS21 (u17) be used?
I´ll appreciate your help!