AM79213 Legerity, AM79213 Datasheet - Page 14

• Manufacturer Part Number: AM79213
• Description: (AM79C203/031 / AM79213) PCM CODEC
• Manufacturer: Legerity

The PCM data can be either 8-bit companded A-law
code, 8-bit companded µ-law code, or 16-bit linear
code. Voice data is transmitted and received via the
PCM highway; control information is written to and read
from the ASLAC/ASLIC devices chip set over the mi-
croprocessor interface.
Besides the CODEC functions, the ASLAC device pro-
vides all the sensing, feedback, and clocking neces-
sary to completely control ASLIC device functions with
programmable parameters. The line status is continu-
ously available in the ASLAC Device Signaling Regis-
ter, which is continuously available via the MPI
interface, or on the PCM highway via a user-program-
mable mode. A programmable interrupt provides add-
ed flexibility in monitoring line status. System-level
parameters under programmable control include ac-
tive and disable loop-current limits, feed resistance,
and apparent battery-feed voltage. The longitudinal
operating point is programmable to optimize the ASLIC
device signal swing capability.
14
Am79213/Am79C203/031 Data Sheet
The ASLAC device provides signals at 12 or 16 kHz for
metering functions. The frequency and level of these
signals are programmable.
The ASLAC device provides extensive loop supervision
capability, including off-hook, ring-trip, and ground-key
detection. Detection thresholds for these functions are
programmable. A programmable debounce timer is
available that eliminates false detection due to contact
bounce. For subscriber line diagnostics, AC and DC line
conditions can be monitored using special test modes.
Results are read using the MPI commands.