FEDL7020-02
1
Semiconductor
ML7020
• SW1CONT
This is the switch for selecting the DTMF reception input.
0: The input amplifier 1 is connected to the DTMF reception circuit.
1: The input amplifier 2 is connected to the DTMF reception circuit.
• SW2CONT
This is the switch for selecting the modem reception and CPT detection inputs.
0: The input amplifier 2 is connected to the modem reception circuit and the CPT detection circuit.
1: The input amplifier 3 is connected to the modem reception circuit and the CPT detection circuit.
• SW3CONT
This is the switch for external circuits, and can be used for connecting the termination, etc.
0: The switch goes into the OFF state.
1: The switch goes into the ON state. (The SWI pin and the SGO pin are connected together.)
• SW4CONT
This is the switch for selecting the signal (TO) of the output amplifier 1.
0: The CPT transmit output is connected to the output amplifier 1.
1: The output signal of SW2 is connected to the output amplifier 1.
• SW5CONT
This is the switch for selecting the signal (LO–, LO+) of the output amplifier 2.
0: The DTMF transmit output is connected to the output amplifier 2.
1: The modem transmit output is connected to the output amplifier 2.
Set this to “1” during the modem transmit mode and set this to “0” during the DTMF transmit mode.
• CPTG_ON
This register is used for the ON/OFF control of call progress tone transmission.
0: CPT transmission becomes OFF and the signal is not output.
1: CPT transmission becomes ON and the signal is output.
• CPT800
This selects the frequency of call progress tone transmission.
0: A 400 Hz signal is output.
1: An 800 Hz signal is output.
• MOD-DT_ON
This is used for the ON/OFF control of modem transmission or DTMF transmission.
The transmission function is made ON/OFF of the block corresponding to the selected mode.
0: Modem transmission or DTMF transmission become OFF and the signal is not output.
1: Modem transmission or DTMF transmission become ON and the signal is output.
In the DTMF transmission mode or in the DTMF loop back mode, PBG3 to 0 are latched at the rising edge of
MOD-DT_ON.
Set this to “0” during the modem reception mode and the tone 1 mode.
• ATT
This controls the attenuator of the DTMF transmission section.
0: No attenuator is inserted. The DTMF transmit signal is output as it is.
1: A –6 dB attenuator is inserted in the DTMF transmission section.
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