User`s manual

Am186™CC Microcontroller Router Reference Design User’s Manual
2-25
POTS Interface
NOTE: See sheets 7, 8, and 9 of the schematics for POTS circuitry.
The Am186CC microcontroller router reference design provides two POTS
connections on RJ-11 connectors (P4 and P5 at locations D-1 and B-1 respectively).
These POTS connections are used to connect standard POTS telephones.
To accomplish this, the reference design’s Am79R79 Ringing SLIC (RSLIC)
device and one half of an Am79C031 DSLAC device provide an interface to plug
in a POTS telephone to communicate across an ISDN B channel.
The basic premise of this type of application is to bring all the functions normally
performed at a central office on a normal POTS line to the user’s home or office
by the ISDN loop. The Am79R79 RSLIC device provides the DC power, ringing,
and supervisory functions to the phone. The Am79C031 DSLAC device provides
the analog voice-to-digital conversion to allow communication to the ISDN
interface transceivers.
The appropriate voltages are provided for the DSLAC and RSLIC devices,
signaling for ring generation to the Am79R79 RSLIC device, and DTMF decoders
that detect dial tone pairs from the POTS telephone, and transfer that information
to the Am186CC microcontroller.
DSLAC PCM Interface
The DSLAC PCM interface connects directly to one of the following:
• Am79C32A S/T transceiver PCM Highway, configured in serial bus port (SBP)
mode
• T7237A U transceiver TDM bus
• Am79C32A S/T transceiver configured in GCI bus mode
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