18
KX-TH1211B/KX-TH1212B/KX-TGA930T
4.8.5.
Telephone Line Interface
Telephone Line Interface Circuit:
Function
• Bell signal detection
• ON/OFF hook and pulse dial circuit
• Side tone circuit
Bell signal detection and OFF HOOK circuit:
In the idle mode, Q141 is open to cut the DC loop current and decrease the ring load. When ring voltage appears at the Tip (T)
and Ring (R) leads (When the telephone rings), the AC ring voltage is transferred as follows:
T
→
L101
→
R111
→
C111
→
Q111
→
DSP pin 58 [BELL]
When the CPU (DSP) detects a ring signal, Q141 turns on, thus providing an off-hook condition (active DC current flow through
the circuit). Following signal flow is the DC current flow.
T
→
L101
→
D101
→
Q141
→
Q161
→
R163
→
R167
→
D101
→
L102
→
P101
→
R
ON HOOK Circuit:
Q141 is open, Q141 is connected as to cut the DC loop current and to cut the voice signal. The unit is consequently in an on-
hook condition.
Pulse Dial Circuit:
Pin 59 of DSP turns Q141 ON/OFF to make the pulse dialing.
Side Tone Circuit:
Basically this circuit prevents the TX signal from feeding back to RX signal. As for this unit, TX signal feed back from Q161 is
canceled by the canceller circuit of DSP.
Summary of Contents for KX-TGA930T - Cordless Extension Handset
Page 2: ...2 KX TH1211B KX TH1212B KX TGA930T ...
Page 34: ...34 KX TH1211B KX TH1212B KX TGA930T 4 15 Signal Route ...
Page 35: ...35 KX TH1211B KX TH1212B KX TGA930T RF part signal route ...
Page 37: ...37 KX TH1211B KX TH1212B KX TGA930T 5 2 Display Indicators ...
Page 38: ...38 KX TH1211B KX TH1212B KX TGA930T 6 Installation Instructions 6 1 Connections ...
Page 42: ...42 KX TH1211B KX TH1212B KX TGA930T 7 1 2 Programming using the Direct Commands ...
Page 43: ...43 KX TH1211B KX TH1212B KX TGA930T ...
Page 44: ...44 KX TH1211B KX TH1212B KX TGA930T ...
Page 45: ...45 KX TH1211B KX TH1212B KX TGA930T 7 2 Error Messages ...
Page 46: ...46 KX TH1211B KX TH1212B KX TGA930T 7 3 Troubleshooting ...
Page 47: ...47 KX TH1211B KX TH1212B KX TGA930T ...
Page 48: ...48 KX TH1211B KX TH1212B KX TGA930T ...
Page 49: ...49 KX TH1211B KX TH1212B KX TGA930T ...
Page 50: ...50 KX TH1211B KX TH1212B KX TGA930T ...
Page 76: ...76 KX TH1211B KX TH1212B KX TGA930T ...
Page 89: ...89 KX TH1211B KX TH1212B KX TGA930T 11 1 2 Handset ...
Page 90: ...90 KX TH1211B KX TH1212B KX TGA930T 11 1 3 Charger Unit ...
Page 91: ...91 KX TH1211B KX TH1212B KX TGA930T 11 2 How to Replace the Handset LCD ...
Page 92: ...92 KX TH1211B KX TH1212B KX TGA930T ...
Page 100: ...100 KX TH1211B KX TH1212B KX TGA930T Memo ...
Page 105: ...105 KX TH1211B KX TH1212B KX TGA930T Memo ...
Page 109: ...109 KX TH1211B KX TH1212B KX TGA930T Memo ...
Page 114: ...114 KX TH1211B KX TH1212B KX TGA930T Memo ...
Page 118: ...118 KX TH1211B KX TH1212B KX TGA930T Memo ...
Page 130: ...130 KX TH1211B KX TH1212B KX TGA930T 15 5 DB56 DSP Package Description ...
Page 134: ...134 KX TH1211B KX TH1212B KX TGA930T 16 3 Cabinet and Electrical Parts Charger Unit ...
Page 135: ...135 KX TH1211B KX TH1212B KX TGA930T 16 4 Accessories and Packing Materials 16 4 1 KX TH1211B ...
Page 136: ...136 KX TH1211B KX TH1212B KX TGA930T 16 4 2 KX TH1212B ...
Page 137: ...137 KX TH1211B KX TH1212B KX TGA930T 16 4 3 KX TGA930T ...