Intelligent Access™ Voice Solutions
BATP
BATL
RSLB
RSPB
CS/RST
DIO/S1
INT
Am79D2251
Dual Intelligent Subscriber Line Audio-Processing Circuit (ISLAC)
DISTINCTIVE CHARACTERISTICS
a73 High performance digital signal processor
provides programmable control of all major
linecard functions
— 32 and 24 kb/s ADPCM to G726, as well as
A-law/µ-law and linear codec
— Transmit and receive gain
— Two-wire AC impedance
— Transhybrid balance
— Equalization
— DC loop feeding
— Smooth or abrupt polarity reversal
— Loop supervision
— Off-hook debounce circuit
— Ground-key and ring-trip filters
— Ringing generation and control
— Adaptive hybrid balance
— Line and circuit testing
— Tone generation
— Metering generation at 12 kHz and 16 kHz
— Envelope shaping and level control
a73 Selectable PCM/MPI or GCI digital interfaces
— Supports most available master clock
frequencies from 512 kHz to 8.196 MHz
a73 0 to 70°C commercial operation
—–40°C to 85°C extended temperature range
available
a73 +3.3 V DC operation
a73 Exceeds LSSGR and ITU requirements
a73 Supports external ringing with on-chip ring-trip
circuit
— Automatic or manual ring-trip modes
a73 DTMF detection according to Q.24
a73 2100 Hz modem tone detection according to V.25
BLOCK DIAGRAM
RC
Networks
and
Protection
A1
B1
A2
B2
Dual
ISLAC
ISLIC
ISLIC
LD1
VREF
7
AGND1
AGND2
RREF
BATH
Ring-Trip
Sense
Resistors
5 5
RSHB
VCCA4
VCCD
DGND1
DGND2
TSCA/G
DRA/DD
DXA/DU
DCLK/S0
PCLK/FS
MCLK
FS/DCL
3
P1-P3
7
LD2
Pub. # 22829 Rev: C Amendment: /0
Issue Date: December 1999