am79231 ETC-unknow, am79231 Datasheet - Page 19

• Manufacturer Part Number: am79231
• Description: Intelligent Subscriber Line Interface Circuit Islic
• Manufacturer: ETC-unknow

Operating Modes
Table 1.
C3
0
0
0
0
1
1
1
1
Note:
1. In these modes, the ring lead (B-lead) output has a –50 V internal clamp to battery ground (BGND).
C2
0
0
1
1
0
0
1
1
Operating Modes
C1
0
1
0
1
0
1
0
1
The Am79231 receives multiplexed control data on the P1, P2 and P3 pins. The LD pin then controls
the loading of P1, P2, and P3 values into the proper bits in the Am79231 control register. When the
LD pin is less than 0.3 V below VREF ( < (VREF – 0.3 V) ), P1–P3 must contain data for relay control
bits RD1, RD2 and RD3. These are latched into the first three bits in the Am79231 control register.
When the LD pin is more than 0.3 V above VREF (> (VREF + 0.3 V) ), P1–P3 must contain ISLIC
control data C1, C2, and C3, which are latched into the last three bits of the Am79231 control register.
Connecting the LD pin to VREF locks the contents of the Am79231 control register.
The operating mode of the Am79231 is determined by the C1, C2, and C3 bits in the control register
of the Am79231. Table 1 defines the Am79231 operating modes set by these signals.
Under normal operating conditions, the ISLIC device does not have active relays. The Am79231 to
ISLAC device interface is designed to allow continuous real-time control of the relay drivers to avoid
incorrect data loads to the relay bit latches of the Am79231 devices.
To perform external ringing, the ISLAC device from the Intelligent Access voice family is set to external
ringing mode (RMODE = 1), enables the ring relay, and puts the Am79231 in the Standby mode.
Standby
Tip Open
On-Hook Transmis-
sion, Fixed Longitudi-
nal Voltage
Disconnect
RSVD
Active High Battery
Active Low Battery
RSVD
Operating Mode
1
1
High Battery
(BATH) and BGND
High Battery
(BATH) and BGND
High Battery
(BATH) and BGND
Low Battery
selection at VBL
High Battery
(BATH) and BGND
Low Battery
(BATL) and BGND
Battery Voltage
Selection
Am79231 Data Sheet
(High ohmic feed): Loop supervision
active, A and B amplifiers shut down
Tip Open: AD at High-Impedance,
Channel A power amplifier shut down
Fixed longitudinal voltage of –30 V
AD and BD at High-Impedance,
Channel A and B power amplifiers
shut down
Active feed, normal or reverse
polarity
Operating Mode
RMGPi & RMGLi
A and B Amplifier
Connection to
Resistors
Output
Open
Open
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