MH88400 Просмотр технического описания (PDF) - Mitel Networks
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MH88400 Datasheet PDF : 10 Pages
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MH88400
Preliminary Information
14
MH88400
TIP
6
VX
Audio Output
13 RLS
TIP
R1
11 TF
VR 7
Audio Input
D1
R2
10 TXIN
4
RVLC
Ring Voltage & Loop
Current Detect Output
RING
Line
Relay
Input
C2
9 RING
3
LC
Loop Control Input
VDD
AGND
1
2
1) R1: 39Ω,1/2W,5%,current
K1
+
limiting resistor for use in
C1
Germany.
2) R2: 18kΩ
+5V
3) C1: 10µF, 6V Tantalum
4) C2: 0.47µF, 100V
NOTES:
5) D1: 180VDC Foldback Diode, e.g. TISP4180, TISP5180
6) VX and VR are biased at 2.5V, therefore, coupling capacitors
may be required depending on application.
C2 must be 0.1µF for correct operation. R2 & C2 form a dummy ringer, where R2 is on the hybrid and C2 must be fitted by
the customer. To initate a manual call, lift the handset. The RVLC pin will indicate that the line as been seized by the
monitor phone. The required number is then dialled and the connections established. During this phase the Loop Control
input should be turned ON to ensure that when the relay K1 is operated and the monitor phone removed from the line loop
current is still maintained. On receipt of the correct progress tones the external controller should control the data transmission
and clear down the call when it is completed by turning the Loop Control OFF. For applications in some countries such as
Germany the MH88422 can not be used with an optional telephone but may still be used in a combined telephone/fax machine.
Figure 4 - Typical Application Circuit with Dummy Ringer and Monitor Phone
TIP
D1
RING
RECEIVE GAIN:
Audio input to Tip-Ring
=20log(R2/(R2+47K))+3.5dB
=6.5dB
14
TIP
13
RLS
R1
11
C2
10
TF
TXIN
MH88400
VX
VR
RVLC
R4
6 R3
1K
1K
7
R2
100K
4
Audio Output
Audio Input
Ring Voltage & Loop
Current Detect Output
9 RING
VDD
1
3
LC
AGND
2
+
Loop Control Input
C1
TRANSMIT GAIN:
Tip-Ring to Audio Output
=20log(R4(R3+R4))-0.4dB
=-6.4dB
Note:
The VX output gain has been reduced by 6dB
(to -6.4dB) and the VR input gain has been
reduced by 10dB (to -6.5dB) in this example.
+5V
1) R1: 39Ω,1/2W,5%,current limiting resistor for use in Germany
2) C1: 10µF, 6V Tantalum
3) C2: 0.1µF, 250V (Typical Value)
4) D1: 180VDC Foldback Diode, e.g. TISP4180, TISP5180
5) VX and VR are biased at 2.5V, therefore, coupling capacitors
may be required depending on application.
6) (R3+R4) should be > 2kΩ to prevent overload.
Figure 5 - Typical Application Circuit for Gain Adjustment
2-18
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