whats the blue thing in the image?On the schematic, I think its the item marked R6 a/r/s AIN1
"audio signal from the iPhone through C1, R1/R2 connected to pin 6 at 2.5V over bias. Threshold for the analog voltage is applied to pin 7. Arduino to iPhone from R3/R4 to split the signal, C2 connected to the terminal through the iPhone microphone. IPhone resistor R5 is needed to be aware that the microphone is connected. R6 is VCC / 2 250mV to adjust the voltage to be much lower."
# Include <SoftModem. H> / / include the library # Include <ctype.h> SoftModem modem; / / SoftModem create an instance of void setup () ( Serial. Begin (57600); modem. begin (); / / setup () call to begin with ) void loop () ( while (modem. available ()) (/ / iPhone verify that data received from int c = modem. read (); / / 1byte Reed if (isprint (c)) ( Serial. Print ((char) c); / / PC sends ) else ( Serial. Print ("("); / / Hex printable characters are displayed in Serial. Print (c, HEX); Serial. Print (")"); ) ) while (Serial. available ()) (/ / PC ensure that the data received from char c = Serial. read (); / / 1byte Reed modem. write (c); / / iPhone send ) )