DS_1x22_017
73M1822/73M1922 Data Sheet
11 Configurable Direct Access Arrangement (DAA)
The 73M1x22 line-side device integrates most of the circuitry to implement a PSTN line interface or DAA
that is capable of being globally compliant with a single bill of materials. The 73M1x22 supports the
following DAA functions:
•
•
•
•
•
•
•
•
Pulse dialing
On and Off Hook switch control
Loop current (DC-IV) regulation
Line impedance matching
Ring detection
Tip and Ring voltage polarity reversal detection
Billing tone rejection
Trans-hybrid cancellation
The device is able to support Barrier-powered mode in which the PSTN loop current may be as low as 8
mA.
11.1 Pulse Dialing
The 73M1x22 supports Pulse Dialing. See Section 11.6 for the description applicable control and status
bits and Section Error! Reference source not found. for a description of a recommended procedure.
11.2 DC Termination
DC Termination or Loop Current (DC-IV) regulation is managed by the 73M1x22 Line-Side Device by
configuring the appropriate registers. No additional components are necessary.
The 73M1x22 provides a DC transconductance circuit that regulates the tip to ring voltage depending on the
DC current supplied by the line. There are four settings that can be used to set the voltage to current ratio.
Figure 31 shows the DC-IV characteristics of the 73M1x22 with special regions of interest.
V
Current Limit Turned on
2.2 kΩ
41 Ω *
Programmable
Turn-on Voltage
Seize Voltage
I
Current Limit Turn-on=42 mA
* ~50 Ω with 8 Ω fuse resistance
Figure 31: DC-IV Characteristics
Rev. 1.6
61
TERIDIAN [ TERIDIAN SEMICONDUCTOR CORPORATION ]
