MH88422
Preliminary Information
VDD
AGND
LC
RVLC
NC
VX
VR
1
2
3
4
5
6
7
14
13
12
11
10
9
8
TIP
RLS
NC
TF
TXIN
RING
NC
Figure 2 - Pin Connections
Pin Description
Pin #
1
2
3
4
Name
VDD
AGND
LC
RVLC
Description
Positive Power Supply Voltage.
+5V.
Analog Ground.
4-Wire Ground. Normally connected to System Ground.
Loop Control (Input).
A logic low activates internal circuitry which provides a dc
termination across Tip and Ring. Used for seizing the line and dial pulsing.
Ring Voltage and Current Detect (Output).
A logic low indicates that loop current is
detected. The loop current can be due to the external monitor phone or the MH88422 in
the off-hook mode. The RVLC output pulses when the external monitor phone is dial
pulsing or when the MH88422 is dial pulsing via the LC input. In addition, when the
MH88422 is on the on-hook mode, a pulsing output indicates ringing voltage across the
Tip and Ring leads. The pulsing output frequency is twice the ringing frequency.
No Connection
should be made to this pin.
Transmit (Output).
4-Wire ground (AGND) referenced audio output, biased at 2.5V.
Outputs in off-hook mode only.
Receive (Input).
4-Wire ground (AGND) referenced audio input, biased at 2.5V. LC
must be activated low and loop current must be flowing.
No Connection
should be made to this pin.
Ring Lead.
Connects to the “Ring” lead of the central office through an optional relay
contact. The central office “Tip” and “Ring” leads may be interchanged.
Transmit (Input).
Connects to the “Ring” lead of the central office through a coupling
capacitor.
Tip Feed.
Connects to the “Tip” lead of the central office through an internal resistor and
an optional external resistor.
No Connection
should be made to this pin.
Ring Loop Sense (Input).
Sense node for ringing voltage detector and the loop current
detector.
Tip Lead.
Connects to the “Tip” lead of the central office through an optional relay
contact. The central office “Tip” and “Ring” leads may be interchanged.
5
6
7
8
9
10
11
12
13
14
NC
VX
VR
NC
RING
TXIN
TF
NC
RLS
TIP
2-22
MITEL [ MITEL NETWORKS CORPORATION ]
