Silicon Laboratories SI2493/57/34/15/04, SI2494/39 manual P0 Even, Q2 Use CTS only

AN93

	Table 42. Extended AT\ Command Set (Continued)
Command	Action
\N2	MNP reliable mode. The ISOmodem attempts to connect with the MNP protocol. If unsuccessful, the
	call is dropped. Compression is controlled by %Cn.
	V.42 auto-reliable—The ISOmodem attempts to connect with the V.42 protocol. If unsuccess-
\N3	ful, the MNP protocol is attempted. If unsuccessful, wire mode is attempted. Compression is
	controlled by %Cn.
\N4	V.42 (LAPM) reliable mode (or drop call)—Same as \N3 except that the ISOmodem drops the call
	instead of connecting in MNP or wire mode. Compression is controlled by %Cn.
	V.42 and MNP reliable mode - The ISOmodem attempts to connect with V.42. If unsuccessful, MNP
\N5	is attempted. If MNP is unsuccessful, the call is dropped. Wiremode is not attempted. Compression
	is controlled by %Cn.
\Pn	Parity type is automatically set in autobaud mode.
\P0	Even
\P1	Space1
\P2	Odd
\P3	Mark.
\Qn	Modem-to-DTE flow control.
\Q0	Disable all flow control—This may only be used if the DTE speed and the line (DCE) speed are guar-
	anteed to match throughout the call.
\Q2	Use CTS only.
\Q3	Use RTS/CTS.
\Q4	Enable XON/XOFF flow control for modem-to-DTE interface. Does not enable modem-to-modem
	flow control.
\Tn	DTE rate2
\T0	300 bps
\T1	600 bps
\T2	1200 bps

Notes:

1.When in autobaud mode, \B0, \B1, and \P1 is not detected automatically. The combination of \B2 and \P3 is detected. This is compatible with seven data bits, no parity, two stop bits. Seven data bits, no parity, one stop bit may be forced by sending AT\T17\B1.

2.After changing the baud rate, the result code OK is sent at the old DTE rate. Subsequent commands must be sent at the new rate. If the ISOmodem is configured in autobaud mode, AT commands \T0 through \T15 lock the new baud rate and disable autobaud. To eliminate any possibility of a race condition between the receipt of the result code and the changing of the UART speed, CTS is de-asserted while the result code is being sent until after the rate has been successfully changed. The host should send the \T command and wait for the OK response. After OK has been received, the host may send data at the new rate as soon as CTS is asserted. The \T command should be the last command sent in a multi-command line and may not be used on the same command line as :U or :R commands. If it is not, the OK from the \T command is sent at the old DTE rate, and other result codes are sent at the new DTE rate.

3.The autobaud feature does not detect this rate.

4.Default is \T16 if autobaud is selected by reset-strap option; otherwise default is \T9 (19.2 kbps).

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