Calling Line Identifier
MX602 - PRELIMINARY INFORMATION
9
Received Character 'n'
START
1
2
3
4
5
6
7
8
STOP
Output of FSK Demod:
IRQ output:
RXCLK input:
RXD output:
1
8
Retimed data bits from
received character 'n'
IRQ
t
t
CHI
t
D
CLO
RXCLK
t
D
t
D
Data Bit 1
Data Bit 2
RXD
t
D
= Internal MX602 delay (max 1µS); t
= RXCLK low time (min 1µS); t
= RXCLK high time (min 1µS)
CHI
CLO
Figure 7: FSK Operation with Data Retiming
Note: If enabled, the Data Retiming block will interpret the FSK Channel Seizure signal (a sequence of alternating mark
and space bits) as valid received characters, with values of 55 (hex). Similarly it may interpret speech or other
signals as random characters. If the Data Retiming facility is not required, the RXCLK input to the MX602 should be
kept high. The asynchronous data from the FSK Demodulator will then be connected directly to the RXD output pin,
and the IRQ output will not be activated by the FSK signal. This case is illustrated in Figure 8.
Received Character 'n'
FSK Demod output:
RXD output:
START
START
1
1
2
2
3
4
5
6
6
7
7
8
8
STOP
STOP
3
4
5
Figure 8: FSK Operation without Data Retiming (RXCLK always high)
4.7 Tone Alert Detector
This block is enabled when the MX602 is set to Tone Alert Detector operating mode. It then monitors the received signal
for the presence of simultaneous 2130Hz and 2750Hz tones of sufficient level and duration.
The MX602 DET output will be set high while a valid Tone Alert signal is detected. At the end of the Tone Alert signal the
DET output will go low and the IRQ output will be pulled low until the MX602 is switched out of Tone Alert Detector mode.
t
DTOFF
Tone Alert signal
Line Signal
DET
t
DTON
IRQ
MODE, ZP
Tone Alert Detect mode
Other mode
See section 6.1 for definitions of t
and t
DTOFF
DTON
Figure 9: Tone Alert Detector Operation
© 1998 MX•COM Inc.
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