Panasonic KX-FT21RS - Manual (Page 148)

9.2. SCHEMATIC DIAGRAM (ANALOG CIRCUIT)
FAX RX, TEL TALK
2V
FAX RX, HANDSET TX
NO PAPER: 5V
PAPER: 0V
FAX TX
FAX RX
12V
2V
2.1V
0V
3.3V
LINE ON/OFF, DIALPULSE
BELL DETECT
5V
0V
KX-FT21RS
148