MH88400
Preliminary Information
VDD
AGND
LC
RVLC
SHK
VX
VR
1
2
3
4
5
6
7
14
13
12
11
10
9
8
TIP
RLS
PHS
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 MH88400 in
the off- hook mode. The RVLC outputs pulses when the external monitor phone is dial
pulsing or when the MH88400 is dial pulses via the LC input. In addition, when the
MH88400 is in the on-hook mode, a pulsing output indicates that ringing voltage is
across the Tip and Ring leads; the pulsing outputs frequency is twice the ringing
frequency.
Switch Hook Detect (Output).
This is an optional output which can be used with the
PHS input and an external phone. When loop current flows from PHS to TIP, SHK goes
to logic low.
Transmit (Output).
4-Wire ground(AGND) referenced audio output, biased at 2.5V.
Outputs for both off-hook and on-hook.
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.
This pin is not connected internally
Ring Lead.
Connects to the “Ring” lead of the central office through a 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.
Monitor Phone Sense (Input).
This is an optional input which can be used with the
SHK output and an external phone. When loop current flows from PHS to TIP, SHK goes
to logic low.
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
SHK
6
7
8
9
10
11
12
VX
VR
NC
RING
TXIN
TF
PHS
13
14
RLS
TIP
2-12
MITEL [ MITEL NETWORKS CORPORATION ]
