&Cn - Select Data Carrier Detect Option

Command Line Format
AT [cmds] &C [suffix] [cmds] <CR>

Suffix Values
0 through 2

Default
&C0

Shipped
&C1

Stored by &Wn
yes

Displayed by &V
yes

Description
This command determines how the state of the Received Line Signal Detector (RLSD) lead relates to the carrier from the distant end. The command takes effect immediately in both the Idle State and the Online Command State.

The behavior of RLSD depends on the &Cn and &Qn commands in effect. Also, RLSD behavior depends on whether online operation is half- or full-duplex. Finally, if &Q5 is in effect, RLSD behavior depends on whether S10=255 or S10<255. Refer to the following tables. Click on the letters in the tables for information about behavior.

RLSD Behaviors for Full Duplex Operation

Command   &C0   &C1   &C2  



&Q0        A     B     D       



&Q1        B     B     B       



&Q2        B     B     B       



&Q3        B     B     B       



&Q4        B     B     B       



&Q5        A     E     A       



&Q6        A     B     D       



&Q5        A     B     D       



S10=255

RLSD Behaviors for Half Duplex Operation

Command   &C0	  &C1	 &C2  



&Q1        E     C     C       



&Q2        E     C     C       



&Q3        E     C     C       



&Q4        E     C     C       



&Q5        A     E     A       



&Q5        A     C     F       



S10=255

Execution Time
Maximum 1 ms

DTE Interface Lines Affected
RLSD

Cross Reference
Commands - &Qn

DTE signals - RLSD

Line signals - Carrier

LEDs - CD

Processes - Hang-up

S-registers - S9 - Carrier Recovery Time , S10

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