Preliminary Information
Pin Description (Continued)
Pin #
17
Name
CA
Description
MH89625C
Control Address (Input):
A three-level digital input which enables PCM input and
output, and determines into which control register (A or B) the serial data, presented to
CSTi, is stored.
Relay Ground:
Return path for relay supply voltage.
Relay Driver 2:
Connects to a user provided external relay coil. A logic high at the SD1
output of the internal MT8967 codec activates this driver. An internal clamp diode from
VRLY to RD2 is provided. This relay is typically used for DID reversals.
Relay Driver 1.
Connects to a user provided external relay coil. A logic high at the SD0
output of the internal MT8967 codec activates this driver. An internal clamp diode from
VRLY to RD1 is provided. This relay is typically used for ringing.
Relay Driver 3.
Connects to a user provided external relay coil. A logic high at the SD2
output of the internal MT8967 codec activates this driver. An internal clamp diode from
VRLY to RD3 is provided. This relay is typically used for in-test.
Relay Driver 4:
Connects to a user provided external relay coil. A logic high at the SD3
output of the internal MT8967 codec activates this driver. An internal clamp diode from
VRLY to RD4 is provided. This relay is typically used for out-test.
Relay Positive Supply Voltage:
Normally +5V. Connects to the relay coil and the relay
supply voltage.
Voltage Reference (Input):
+2.50V for the internal codec.
Internal Connection:
This pin is internally connected.
Internal Connection:
This pin is internally connected
Internal Connection:
This pin is internally connected
Internal Connection:
This pin is internally connected
Internal Connection:
This pin is internally connected
Analog Ground.
Analog and Digital Ground. Connects to System Ground.
Positive Supply Voltage
(+5V)
Loop Current Adjust (Input).
The maximum constant loop current is a function of the
resistance connected from this pin to V
EE
. Normally left open
Internal Connection.
This pin is internally connected.
Battery AC Component (Input).
AC noise present in the V
BAT
supply, isolated from the
DC component, can be applied to this pin to reduce longitudinal noise on TIP and RING.
To implement this feature, connect a 0.1µF 100V capacitor from V
BAT
to VAC, and a 1kΩ
resistor from VAC to AGND. This pin must be tied to AGND when not used.
Gain Setting (Input).
A logic low at this input adds an additional -0.5dB gain in the
receive direction (DSTi to Tip-Ring). This gain is in addition to the gain set by the Codec.
A logic high adds 0dB gain.
Loop Ground.
Return path for the battery (V
BAT
) supply voltage. Connects to System
Ground.
Battery Supply Voltage.
Normally -48V.
Internal Connection:
This pin is internally connected
Internal Connection:
This pin is internally connected
Internal Connection:
This pin is internally connected
18
19
RGND
RD2
20
RD1
21
RD3
22
RD4
23
24
25
26
27
28
29
30
31
32
33
34
V
RLY
V
Ref
IC
IC
IC
IC
IC
AGND
V
DD
LCA
IC
VAC
35
GS
36
37
38
39
40
LGND
V
Bat
IC
IC
IC
2-271
MITEL [ MITEL NETWORKS CORPORATION ]
