Evaluation Kit for CMX612
EV6120
1.6.1.2 CMX612 Detector Signal Paths.
There are two input signal path options with the CMX612, AOP1 and AOP2. AOP1 is connected
directly across the line and AOP2 forms the rx side of the 2- to 4-wire interface.
The LED marked ‘IP’ indicates the state of the CMX612 input select pin.
Note that if the signal path chosen is via the 2- to 4-wire interface absolute levels at the CMX612 will
depend upon the line impedance of the caller ID simulator in use and on the quality of the termination
of that line. This will have a bearing on decode and not-decode levels.
1.6.1.3 External Phone
A second RJ11 socket, J2, is provided for an external telephone when the EV6120 is demonstrating
adjunct box functions. The relay, RLY1, which is normally closed will mute the external telephone.
When muted/disabled the LED marked ‘MUTE’ is illuminated.
1.6.1.4 Speech Paths
When emulating a feature phone, a mutable local speech path is available. A speech signal may be
input at either testpoint TP6, jack socket J4, or from a telephone handset (not provided) connected to
socket J3. When muted the LED marked ‘MUTE’ is illuminated.
Note that the local speech path (input at TP6 or J4) has a gain of ≈6dB.
Far end signals are routed from the rx output of the hybrid ( CMX612: AOP2 ), via op-amp U1:A, to
the handset connector socket, J3.
1.6.1.5 DTMF Acknowledgement Code
The DTMF acknowledgement (digit D) for the type2 / off-hook / cidcw demonstrations is generated by
U5 (CMX615) and fed to the Tx input of the 2- to 4-wire interface.
1.6.1.6 Operating Voltage
The operating voltage (V ) is set to 3.3Volts. This may be altered by changing components R62 and
DD
R29 which are socketed. To select 5.0Volts set R62 = 620Ω and R29 = 100Ω. The formula for
calculating the values of R68 and R69 is as follows:-
240 (VDD −1.25)
R62 + R29 =
1.25
Where 240 is the value of R14 in ohms and V is the required supply voltage.
DD
1.6.1.7 Clocks and Oscillators
•
The CMX612 may use either an external clock or its own xtal oscillator. A 3.58MHz xtal is
provided on-board for the latter method. Two jumpers JP2 and JP3, which are normally fitted,
select the xtal oscillator. An external clock may be supplied to JP2 pin 2 once the jumpers have
been removed.
•
•
The PIC16C74A may be provided with an external clock in the same way by removing jumpers
JP5 and JP6. Note that PICs programmed by CML are only configured for use with the on-board
4MHz crystal.
The DTMF generator ( CMX615 ) uses the clock from the CMX612. This device cannot be
enabled when the CMX612 is in zero power mode.
Consumer Microcircuits Limited
13
2000
UM6120/1
CMLMICRO [ CML MICROCIRCUITS ]
