Preliminary Information
MH88600
C1=C2=10µF, 10V Electrolytic
or tantalum
C3=1nF, 250V, 20%
C3 is recommended to
improve stability when
RV1
used on loop lengths less
than 500Ω total or used
with active loads
Z=G x Zo
R=565.68 x G
Ω
G may be chosen to
Zo
suit preferred component
values (useful for
capacitive elements);
resistive elements should
have values in the range
of 1k to 1MΩ. Typical values RV2
are G = 10
See Table 2 for external
network examples.
Set Rp=1MΩ for networks
not specifying an Rp
RINGING
GENERATOR
90VRMS
20Hz
+ve
RELAY
SUPPLY
External Network
Z
R
40
10
ZN13
TF1
ZN8
27
ZN6
21
ZN1
PG3
9
TF2
TX
6
C3
5
4
K1
3
K1
16
K1
14
VRR
GNDA
VRef
VDD
VBat
LCA
VEE
RC
25
26
VX
TIP
MH88600
CODEC
RING
RF2
RF1
RD
PG4
22
VR
EGB
SHK
GNDBat
19
18
~
15 17 20 13
12
2
11
8
RINGING
CONTROL
Cp
Z
=
Rp
Rs
C1
-5V
+5V
C2
Figure 8 - Using an External Network to Match any Zo
2-95
MITEL [ MITEL NETWORKS CORPORATION ]
