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Technical Reference >

Introduction to Syntax and Procedures

Data Command Set

• Generic Modem Commands
• DTE Interface
• Call Control
• Modulation Control Commands
• Error Control Commands
• Data Compression Commands
• Diagnostic Commands
• V.92 +P Commands
• S Parameters

Result Codes

Glossary

Regulatory Information

Limited Warranty

Modulation Control Commands

+MS - Modulation Selection

This extended-format compound parameter controls the manner of operation of the modulation capabilities in the modem. It accepts six subparameters.

Syntax

+MS=[<carrier>[,<automode>[,<min_tx_rate>[,<min_rx_rate>
[,<max_rx_rate>]]]]]
Where possible<carrier>,<min_tx_rate>,<max_tx_rate>,<min_rx_rate>, and <max_rx_rate> values are listed in Table 3-2.

Defined Values

<value> A string which specifies the preferred modem carrier to use in originating or answering a connection. <carrier> values are strings of up to eight characters, consisting only of numeric digits and upper case letters. <carrier> values for ITU standard modulations take the form: <letter><1-4digits><other letters as needed>. Defined values are listed in Table 3-2.

<automode> A numeric value which enables or disables automatic modulation negotiation (e.g., ITU-T V.32bis Annex A or V.8).

<min_rx_rate> and <max_rx_rate> Numeric values which specify the lowest (<min_rx_rate>) and highest (<max_rx_rate>) rate at which the modem may establish a receive connection. May be used to condition distinct limits for the receive direction as distinct from the transmit direction. Values for this subparameter are decimal encoded, in units of bit/s. The possible values for each modulation are listed in Table 3-2. Actual values will be limited to possible values corresponding to the entered and fall-back as determined during operation. (Default = lowest (<min_rx_rate>) and highest (<max_rx_rate>) rate supported by the selected carrier.)

<min_tx_rate> and <max_tx_rate> Numeric values which specify the lowest (<min_tx_rate>) and highest (<max_tx_rate>) rate at which the modem may establish a transmit connection. Non-zero values for this subparameter are decimal encoded, in units of bit/s. The possible values for each modulation are listed in Table 3-2. Actual values will be limited to possible values corresponding to the entered and fall-back as determined during operation. (Default = lowest (<min_tx_rate>) and highest (<max_tx_rate>) rate supported by the selected carrier.)

Reporting Current or Selected Values

Command: +MS?
Response: +MS:,<carrier>,<automode>,<min_tx_rate> <max_tx_rate>,<min_rx_rate>,<max_rx_rate>

Note: The current active settings are reported under control of the +MR parameter.

Example: +MS: K56, 1,300,33600,300,56000

For default values. This example allows maximum system flexibility to determine optimal receive and transmit rates during operation.

Reporting Supported Range of Parameter Values

Command: +MS=?
Response: +MS: (< carrier> range),(<automode> range),
(<min_tx_rate> range),( <max_tx_rate> range), ( <min_rx_rate> range), (<max_rx_rate> range)

Example 1: +MS:(B103,B212,V21,V22,V22B,V23C,V32,V32B,V34, K56,V90),(0,1),(300-33600),(300-33600),(300-56000),(300-56000)

Example 2: +MS:(B103,B212,V21,V22,V22B,V23C,V32,V32B,V34, V90,V92),(0,1),(300-33600),(300-33600),(300-56000),(300-56000)

Result Codes

+MR - Modulation Reporting Control

This extended-format numeric parameter controls whether or not the extended-format +MCR:<carrier> and +MRR:<rate> intermediate result codes are transmitted from the modem to the DTE. If enabled, +MCR: <carrier> and +MRR:<rate> intermediate result codes represent the current (negotiated or renegotiated) modulation<carrier> and <rate> that are transmitted at the point during connect negotiation (handshaking) at which the modem has determined which modulation and rate will be used, i.e., before any Error Control or Data Compression reports are transmitted, and before any final result code (e.g., CONNECT) is transmitted.

S95 bit 2 is reset to 0 for +MR=0 and is set to a 1 for +MR=1 or +MR=2. The more recent setting of +MR or S95 bit 2, and the W command setting, determines modulation result code reporting (see S95 Parameter and W Command).

Syntax

+MR=[<value>]

Defined Values

<value> A decimal number corresponding to the selected option:

Reporting Current or Selected Values

Command: +MR?
Response: +MR: <current value>
Example: +MR: 0 For default setting

Reporting Supported Range of Parameter Values

Command: +MR=?
Response: +MR: (<value>range)
Example: +MR: (0-2)

+MCR: Report Syntax

Response: +MCR: <carrier>

<carrier> Alphanumeric code corresponding to the reported carrier. Defined values are:

B103 For Bell 103
B212 For Bell 212
V21 For V.21
V22 For V.22
V22B For V.22bis
V23C For V.23
V32 For V.32
V32B For V.32bis
V34 For V.34
K56 For K56flex
V90 For V.90
V92 For V.92

+MRR: Report Syntax

Response: +MRR: <tx_rate>, <rx_rate>
<rx_rate> Decimal transmit rate in bits/s.
<rx_rate> Decimal receive rate in bits/s.
Example: +MRR: 28800, 48000

B - CCITT or Bell

When the modem is configured to allow either option, the modem will select Bell or CCITT modulation for a line speed connection of 300 or 1200 bps. Any other line speed will use a CCITT modulation standard. The parameter value, if valid, is written to S27 bit 6.

Syntax

B<value>

Defined Values

<value> Decimal number corresponding to the selected option.

Result Codes