CMX602BD4 MX-COM, Inc., CMX602BD4 Datasheet - Page 12

• Manufacturer Part Number: CMX602BD4
• Description: Calling line identifier plus call waiting
• Manufacturer: MX-COM, Inc.

Calling Line Identifier plus Call Waiting (Type II)
4.10 Xtal Osc and Clock Dividers
A 3.579545MHz clock present at the XTAL pin determines frequency and timing accuracy of the CMX602B.
This may be generated by the on-chip oscillator inverter using the external components C1, C2, and X1 of
Figure 2, or may be supplied from an external source to the XTAL input, in which case C1, C2, and X1 should
not be fitted.
The oscillator is turned off in the 'Zero-Power' modes.
If the clock is provided by an external source which is not always running, then the ZP input must be set high
when the clock is not available. Failure to observe this rule may cause a significant rise in the supply current
drawn by CMX602B as well as generating undefined states of the RXD, DET, and IRQ outputs.
5. Application
5.1 'On-Hook' Operation
The systems described in this section operate when the telephone set is not in use (on-hook) to display the
number of a calling party before the call is answered. System specific descriptions are provided as well as a
flowchart for on-hook applications (Figure 13).
5.1.1 Bellcore System
Figure 11 illustrates the line signaling and CMX602B input and output signals for the Bellcore 'On-Hook'
Caller ID system as defined in Bellcore documents GR-30-CORE and SR-TSV-002476 and also in ETS 300
659-1 Section 6.1.1.
As for the British Telecom system, the 'Chan Seize' signal is a '1010…' FSK bit sequence. The Bellcore
specifications do not require AC or DC line terminations while the FSK data is being received, however ETS
300 659-1 allows for the possibility of an AC termination begin applied.
Note: For simplicity of presentation, the Data Retiming function is not used in Figure 11 (RXCLK is kept high).
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SIGNALING
2000 MX-COM, Inc
MODE
RXD
DET
IRQ
RD
RT
ZP
FIRST
RING
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Figure 11: Bellcore On-hook System Signals
250ms
CHAN
SEIZE
250ms
FSK IDLE
FSK IDLE
12
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MARK
150ms
3400 to 4400 ms
MESSAGE
CMX602B PRELIMINARY INFORMATION
FSK DATA
FSK DATA
FSK DATA
Doc. # 20480204.002
200ms
RINGING