CMX624 Ver la hoja de datos (PDF) - CML Microsystems Plc

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Fabricante

CMX624

V.23 / Bell 202 Modem

CML Microsystems Plc 

V23 / Bell 202 Modem

CMX624

0

-10

Bell 202

-20

-30

dBm

V23

-40

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100000

Figure 5 Maximum Out of Band Tx Line Energy Limits

1.5.8 Transmit Output Buffer

This buffer amplifier, connected to the TXN, TXO and TXON pins, is intended for use as a Tx line driver as

shown in Section 1.6.1. Two symmetrical outputs are provided for use with a balanced load to give

sufficient Tx line signal levels even at low VDD. If this is not required the TXON output can be disabled.

If the buffer is used as a balanced line driver, then bit 6 of the SETUP Register should be set to ‘1’ (TXON

output enabled). Setting bit 6 to ‘0’ disables the TXON output and the buffer draws less current from the

supply. When bit 6 is set to '0' the TXON pin should be left open circuit. N.B. The TXO output is unaffected

by this bit.

1.5.9 Ring Signal Detector

This block, which functions even in Zero Power mode, can be used to detect a telephone line Ring Signal

or Line Voltage Reversal and then generate a Interrupt Request signal to wake up the µC at the start of a

call. Suitable interface circuits are shown in Section 1.6.2.

The output of this block is the ‘Ring Detect’ line shown in Figure 1 which directly drives bit 6 of the FLAGS

Register. Any ‘0’ to ‘1’ or ‘1’ to ‘0’ change on this line will also set the ‘Ring Detect Change’ bit (5) of the

FLAGS Register.

If this block is not used, then the RD and RT pins should be connected to VSS and the ‘Ring Detect

Change’ bit (5) of the IRQ MASK Register set to ‘0’.

 2003 CML Microsystems Plc

10

D/624/7

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