Preliminary Information
Pin Description (Continued)
Pin #
19
Name
NATT
Description
MH88625
Network Balance AT+T Node.
Connects to N1 for a network balance impedance of AT&T
compromise (350Ω + 1kΩ // 210nF); the device’s input impedance must be set to 600Ω. This
node is active only when NS is at logic high. This node should be left open circuit when not
used.
Network Balance Node 1 (Input).
0.1 times the impedance between pins N1 and N2 must
match the device’s input impedance, while 0.1 times the impedance between pins N1 and
AGND is the device’s network balance impedance. This node is active only when NS is at
logic high. This node may be terminated when not used (i.e., NS at logic low).
Network Balance Node 2 (Output).
See N1 for description.
Line Impedance 900Ω Node.
Connects to Z1 for a line impedance of 900Ω. This node
should be left open circuit when not used.
Line Impedance Node 1 (Input).
0.1 times the times the impedance between pins Z1 and
Z2 is the device’s line impedance. This node must always be connected.
Line Impedance Node 2 (Output).
0.1 times the times the impedance between pins Z1 and
Z2 is the device’s line impedance. This node should be left open circuit when not used.
Transmit (Output).
4-Wire (AGND) referenced audio output.
Receive (Input).
4-Wire (AGND) referenced audio input.
Transmit Gain Node 0.
Connects to GTX1 for 0dB transmit gain.
Transmit Gain Node 1.
Connects to a resistor to AGND for transmit gain adjustment.
Receive Gain Node 0.
Connects to GRX1 for 0dB gain.
Receive Gain Node 1.
Connects to a resistor to AGND to receive gain adjustment.
Internal Connection.
This pin is internally connected and must be left open.
Line Impedance 600
Ω
Node (Output).
Connects to Z1 for a line impedance of 600Ω. This
pin should be left open circuit when not used.
Network Balance Setting (Input).
The logic level at NS selects the network balance
impedance. A logic 0 enables an internal balance equivalent to the input impedance (Zin).
While a logic 1 enables an external balance 0.1 times the impedance between pins N1 and
AGND balanced to 0.1 times the impedance between pins N1 and N2. The impedance
between N1 and N2 must be equivalent to 10 times the input impedance (Zin).
Off-Hook Indication (Output).
A logic low output indicates when the subscriber equipment
has gone Off-Hook.
Unbalance Detect (Output).
A log IC low output indicates when the DC current flow in the
Tip and Ring leads is unbalanced, indicating that the subscriber equipment has grounded
the Ring lead.
Internal Connection.
These pins are internally connected and must be left open
Negative Supply Voltage.
-5V dc.
Positive Supply Voltage.
+5V dc.
20
N1
21
22
23
24
25
26
27
28
29
30
31
32
33
N2
Z900
Z1
Z2
TX
RX
GTX0
GTX1
GRX0
GRX1
IC
Z600
NS
34
SHK
35
UD
36,37,38
IC
V
EE
V
DD
39
40
2-185
MITEL [ MITEL NETWORKS CORPORATION ]
