3.
Issue the OK result code, and set the parameter value to the valid value nearest to that
specified in the command line.
The description of each command specifies which of these three techniques is used to handle
invalid parameter values for that command or parameter.
2.7 Modem Responses
While in command state and online command state, the modem will issue responses using the
same rate, word length, and parity as the most recently received DTE command line. In the
event that no DTE command has yet been received, rate, word length, and parity used will
depend on the capabilities of the modem.
When the modem transitions from the command state or online command state to the online
data state, the result code
CONNECT
should be issued at the bit rate and parity used during
the command state. When the modem transitions from the online data state to the command
state or online command state, the result codes should be issued at the bit rate used during the
online data state. Thereafter, any unsolicited result codes should use the bit rate and parity of
the last command line issued by the DTE to the modem.
The characters of a response will be contiguous, with no more than 100 milliseconds of mark
idle issued between characters in addition to stop elements.
2.7.1 Responses
There are two types of responses that may be issued by the modem: information text and result codes.
Information Text.
Information text responses consist of three parts: a header, information
text, and a trailer:
1.
The characters transmitted for the header are determined by the V command.
2.
The trailer consists of two characters, being the character having the ordinal value of
parameter S3 followed by the character having the ordinal value of parameter S4.
3.
Information text usually consists of a single line; information text returned in response to
some commands may contain multiple lines, and the text may therefore include CR, LF,
and other formatting characters to improve readability.
Result Code Parts.
Result codes consist of three parts: a header, the result text, and a trailer.
1.
The characters transmitted for the header and trailer are determined by the V command setting.
2.
The result text may be transmitted as a number or as a string, also depending on a the V
command setting.
Result Code Types.
There are three types of result codes: final, intermediate, and unsolicited.
Result codes are described in Section 3.5.
1.
A final result code indicates the completion of a full modem action and an ability to
accept new commands from the DTE.
2.
An intermediate result code is a report of the progress of an modem action. The
CONNECT result code is an intermediate result code. In the case of a dialing or
answering command, the modem switches from command state to online data state, and
issues a CONNECT result code. This is an intermediate result code for the modem
because it cannot accept commands from the DTE while in online data state. When the
modem switches back to the command state it then issues a final result code (such as OK
or NO CARRIER).
3.
Unsolicited result codes (such as RING) indicate the occurrence of an event not directly
associated with the issuance of a command from the DTE.
2.7.2 Extended Syntax Result Codes
Extended syntax result codes may be issued in response to either basic or extended
commands, or both. The appropriate responses are specified in the definitions of the
commands, the responses, or both.
The general format of extended syntax result codes is the same as result codes defined in TIA-
602 with regard to headers and trailers. The characters specified in S-parameters S3 and S4
are used in headers and trailers of extended syntax result codes as they are in basic format
