Pads 1, 2 & 3 are the left & right audio
inputs & ground connection.
Pads 4 & 5 are the audio output & ground connections.
Pads 6 & 7 are the telephone jack connections.
Pads 8, 9 & 10 are the power supply connections.
Phone to Sound Card Parts List
| C1, thru C4 - 100uf Electrolytic Capacitor
C5 - .001uf Ceramic Capacitor
C6 - .033uf Capacitor
C7 - .01uf
C8 - 4.7uf
IC1, IC2 - NE5532
R1, R2 - 10K
R3 - 100K
R4 - 1K
R5 - 2.2K
R6, R7 - 22K
R8 - 10K
R9 - 470
R10 - 910 1/2 watt
R11 - 1K 1/2 watt
R12 - 10K Trimmer or Potentiometer
T1 - Midcom 671 - 8005
Phone jack RJ11
Microphone plug 3.5mm & cable
Stereo audio plug 3.5mm & cable
R10 and R11 are 1/2 watt resistors connected in parallel to dissipate heat and to achieve about 480 ohms to provide the current flow needed for a conventional landline telephone to operate.
Circuit Board Component layout.
Viewing traces thru top of the circuit board.