Document
AG8889 CALL WAITING DECODER
I.
GENERAL DESCRIPTION
This is a new version of Call Waiting service decoder on the telephone. Call Waiting service works by alerting a customer engaged in a telephone call to a new incoming call. This way the customer can still receive important calls while engaged in a current call. The Call Waiting decoder can detect dual tone (2130Hz and 2750Hz) alert signal and generate a valid signal on the data pins for micro controller.
II.
FEATURES
• • • • • • Compatible with Bellcore special report SR-TSV-002476 3.6V ~ 6.0V supply voltage Call-Waiting (2130Hz plus 2750Hz) Alert Signal Detector Good talkdown and talkoff performance Sensitivity compensated by adjusting input OP gain Package series --- 14-pin DIP or 16-pin SOP (150 mil) AG8889AP for 14-pin DIP AG8889N for 16-pin SOP (150 mil)
III. APPLICATION
• Feature phones • Cordless phones • Adjunct unit (stand alone)
IV. PIN CONFIGURATION
AG8889AP
TIP RING OPO VREF NC PWD VSS
1 2 3 4 5 6 7 14 13 12 11
AG8889N
VDD DO NC NC NC OSCI OSCO TIP RING OPO VREF NC PWD VSS NC
1 2 3 4 5 6 7 8 16 15 14 13
VDD DO NC NC NC OSCI OSCO NC
10
9 8
12
11 10 9
* This specification are subject to be changed without notice.
8.8.2000
1
AG8889 CALL WAITING DECODER
V.
FUNCTIONAL BLOCK DIAGRAM
OPO
TIP RING
Tone Filter Detection Block
DO
VREF
Vdd/2
Voltage Reference
Clock Generator
OSCI OSCO
PWD
VI. PIN DESCRIPTIONS
Pin TIP RING OPO VREF PWD I/O I I O I Description Tip in should be connected with twisted pair Ring in should be connected with twisted pair Output of OP Amp Reference voltage Vref = 1/2 Vdd This pin is normal low enabling chip on normal operation and ready to detect CAS tone signals. This active high input sets the chip into power down mode and disable oscillator to save power. 3.58MHz oscillator in 3.58MHz oscillator out DO : used as output, this pin determines whether DO signal is valid or not. High is valid. Normal low. Power Ground Non connected
OSCI OSCO DO VDD GND NC
I O O
VII. FUNCTIONAL DESCRIPTIONS
Call Waiting service works by alerting a customer engaged in a telephone call to a new incoming call. This way the customer can still receive important calls while engaged in a current call. The CALL WAITING DECODER can detect CAS(Call-Waiting Alerting Signal 2130Hz plus 2750Hz) and generate a valid signal on the data pin. The call waiting decoder is designed to support the Caller Number Deliver feature, which is offered by regional Bell Operating Companies. The call waiting decoder has three blocks, including differential amplifier, tone filter detection block In a typical application, this IC receives Tip and Ring signals from twisted pairs. The signals as inputs of differential amplifier, and the differential amplifier sends input signal to a band pass tone filter. Once the signal is filtered, the digital detection block decodes the information. The output data made available at DO pin. This IC is used for detecting CAS signals. Once the signal is detected, the detection indication is shown on the data output DO pin. The DO pin is normal low. When this IC detects 2130Hz and 2750Hz frequency at the same time, then DO pin goes to high. * This specification are subject to be changed without notice. 2 8.8.2000
AG8889 CALL WAITING DECODER
DC CHARACTERISTIC
VDD=5V, Vss=0V, Ta=25°C, fOSC=3.58MHz Sym. VDD IDD VIL VIH VOL Description operating supply voltage operating supply current low level input voltage high level input voltage low level output voltage 3.5 load=1mA 0.4 4.6 Condition Min. 3.6 Typ. 3.3 Max. 6 5 1.5 Unit V mA V V V V
VOH high level output voltage load=1mA Note: 1.both tones in the composite signal have equal amplitude. 2.tone pair is deviated by 0.5%. 3.addes a 0.1uf capacitor between Power and Ground.
AC ELECTRICAL CHARACTERISTIC
(VDD=+5V,Ta=+25°C) CHARACTERISTIC Input sensitivity TIP and RING pins ,Vdd=+5V, Input G=1 Input frequency tolerance for 2130Hz Input frequency tolerance for 2750Hz Min. Typ. -38 ±1.2 ±1.2 Max. Unit dBm % %
* This specification are subject to be changed without notice.
8.8.2000
3
AG8889 CALL WAITING DECODER
WAVE FORM TIMING
DO timing:
line event normal on hook
off hook engaged call
alert tone (~80ms)
Tvd
CAS
Tvd=Tfvd+Tdvd Tinvd=Tfinvd+Tdinvd Tfvd Tdvd
Tinvd Tfinvd Tdinvd
OSC timing:
power off Power on/off PWD Tosc
power on
OSCI
(OSCO)
OSC off
OSC on
Tosc OSC off
Sym. Tfvd Tfinvd Tdvd Tdinvd Tvd Tinvd alert tone Tosc
Description filter output signal valid delay filter output signal invalid delay digital delay of valid signal digital delay of invalid signal total delay of valid signal total delay of invalid signal input alert tone length (2130 ,2750 Hz @ -20dBm ) Oscillator enable delay time
Min.
Typ. 6 6 36 20 42 26 80
Max.
Unit ms ms ms ms ms ms ms ms
10
Note: detected alert tone length shown above is assumed that no speech signals input. test under alert tone signal = -22dBm (600Ω)
* This specification are subject to be changed without notice.
8.8..