73M2901CE-IMR/F 查看數據表（PDF） - Teridian Semiconductor Corporation

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73M2901CE-IMR/F

V.22bis Single Chip Modem

Teridian Semiconductor Corporation 

73M2901CE Data Sheet

DS_2901CE_031

or 129 to 255 when not checking frequency. The practical range is from 3 to 30 when checking

frequency, depending on the transformer, Caller ID series resistor, capacitor, and the ring frequency.

The other ring parameters such as ring frequency (S17 and S18) and cadence (S51-S58) still need to be

programmed when using energy ring detection.

The typical initialization string for ring detection and auto answer for the U.S. would be:

ATS123=7S0=1<CR><LF>

For other countries, the other ring parameters should also be individually programmed, or the S99

register can be used to program all the country parameters.

6.4.4 Caller ID Mode Changes

The Caller ID modes have also had some enhancements. There is now two different types of TYPE II

caller ID; normal TYPE II and snoop mode TYPE II.

Normal TYPE II Caller ID is on when S110 bit 3 is turned on. The modem must be off hook (in use) for

this mode to be active. When the modem detects an alerting tone telling it that a call is waiting and that a

Caller ID message is about to be sent, the modem then sends a DTMF digit “D” to notify the CO that A

TYPE II Caller ID device is present. The CO then sends the Caller ID message, and after receiving the

message the 73M2901CE will go on-hook (hang up).

TYPE II snoop mode is enabled when S95=$99 (99 hex). In this mode the modem will report either a

TYPE I or TYPE II Caller ID message when the modem is on hook. If another Caller ID device is off hook

the modem will detect the Caller ID handshake and output the Caller ID data, but the 73M2901CE will not

actively participate otherwise.

TYPE II Caller ID performance has been improved and, using proper coupling circuitry to monitor the CID

signal, the 73M2901CE can pass all EIA-777A tests.

6.4.5 Selectable Answer Tone Frequency Detection

It is now possible to select which frequencies will be detected as an answer tone during the handshake.

A new S register, S120, has been added for this purpose. This adds some flexibility to the handshake in

dial-up applications. The register bit definitions are as follows:

Bit 0 1650Hz – V21 Marks (default)

Bit 1 1300Hz – V23 Marks

Bit 2 2100Hz – ITU Answer Tone (default)

Bit 3 Reserved

Bit 4 2225Hz – Bell Answer Tone (default)

Bit 5 2250Hz – S0 (default)

Bit 6 Reserved

Bit 7 Reserved

6.4.6 73M2901CE S99 Country Code Support

A feature of the 73M2901 family of modem ICs is the country configuration register S99. This register

can be used to program a variety of country parameters with a single register setting. See the

73M2901CE AT Command User Guide if the countries you are interested are not listed for S99; the

individual parameters can still be programmed through the S-registers. Tables with all the register

settings controlled by S99 are provided. By finding the country with the settings closest to what are

required, you can minimize the number of registers that need to be programmed. The following

information can be used to tailor the behavior of the 73M2901CE for specific support for countries not

listed for S99.

18

Rev. 3.4

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