73M2901CE-IMR/F Maxim Integrated Products, 73M2901CE-IMR/F Datasheet - Page 19

• Manufacturer Part Number: 73M2901CE-IMR/F
• Description: IC MODEM 3.3V V.22BIS 32-QFN
• Manufacturer: Maxim Integrated Products

Specifications of 73M2901CE-IMR/F

• Data Format: V.21, V.22, V.23, Bell 103, Bell 212A
• Baud Rates: 300 ~ 9.6k
• Interface: Serial
• Voltage - Supply: 2.7 V ~ 3.6 V
• Mounting Type: Surface Mount
• Package / Case: 32-VFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

DS_2901CE_031
73M2901CE Data Sheet
6.4.6.1 Ring Detection Parameters
The ring detector is programmable in a number of ways. S-registers S17 and S18 control the frequency
range of the ring frequencies that are valid. Ringing tones outside these settings will not be detected.
S-registers S51-S58 determine the cadences (on and off timing of the tones) that are allowed. Either one
of two different cadences can be accepted or a dual cadence can be defined, depending on the setting of
bit 6 in register S29. S123 enables the energy ring detection feature. With S123 set to 0, energy ring
detection is disabled and the optocoupler input is used as in the 73M2901CL. With S123 set to a
non-zero number, the amplitude threshold and whether the ring frequency is checked can be controlled.
6.4.6.2 Dial Tone Parameters
The dial tone parameters can also be controlled over a wide range. S29 controls whether a continuous
dial tone (bit 7=1, the default), one of two different single cadences (bit 4=0, default) or a dual cadence
(bit 4=1) dial tone will be detected. Registers S35 – S42, control the two cadences’ on and off times.
There is also control for the tones that are detected as valid. Register S20 controls whether precise
frequencies will be detected or a band of frequencies selected as a valid. S20 also selects whether an
individual tone or all tones selected by S19 must be detected. The low nibble of register S19 selects
which tones will be used for dial tone detection. Register S88 selects the imprecise frequency range for
imprecise detection mode.
In addition register S66 determines the maximum time to wait for dial tone, S67 the tone qualification
duration, and S75 and S77 select the minimum level for detection for imprecise and precise tones,
respectively.
6.4.6.3 Busy Tone Parameters
The busy tone parameters can also be controlled over a wide range. S29 controls whether one of two
different single cadences (bit 5=0, default) or a dual cadence (bit 5=1) dial tone will be detected.
Registers S43 – S50, control the two cadences’ on and off times.
There is also control for the tones that are detected as valid. Register S20 controls whether precise
frequencies will be detected or a band of frequencies selected as a valid tone. S20 also selects whether
an individual tone or all tones selected by S19 must be detected. The high nibble of register S19 selects
which tones will be used for busy tone detection. Register S88 selects the imprecise frequency range for
imprecise detection mode.
In addition, registers S76 and S78 select the minimum level for detection for imprecise and precise tones,
respectively.
6.4.6.4 Pulse Dialing
Registers S32 through S34 control the timing of pulse dialing. S32 sets the duration of off hook switch
closure (make time). S33 controls the off hook open time (break time). S34 controls the time between
digits. S32 and S33 times are in ms, while S34 is in 10 ms increments.
Some countries use different pulse patterns to represent the digits, so S72 can be used to set the pulse
pattern so digits are correctly sent. The default is the most common, where the digit equals the number
of pulses, except for 0, which is 10 pulses.
6.4.6.5 DTMF Dialing
DTMF on and off timing can be adjusted by S11. The requirements for the timing can vary with different
countries. The DTMF transmit levels can be adjusted using the upper nibble of register S13 and the twist
(level of the lower frequency relative to the higher frequency) can be changed using S12 bits 4-6.
Additional adjustment of the transmit level is provided by S85, but setting S85 at too high of a level can
also increase the THD, so restraint is advised. DTMF should be transmitted at the highest level allowed
by country specific limitations, but do not exceed this limit.
Rev. 3.4
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