Digi W manual Originating, Answering, and Disconnecting Calls

Originating, Answering, and Disconnecting Calls

In the following table, an application requests a TCP session with the Digi device server. The table displays the responses of the Digi device server and application as they negotiate a TCP connection.

Application AT Com-	Digi Device Server Response	Notes
mand
AT&F	OK.	AT command request to restore defaults to factory set-
		tings-Digi device server responds OK.
	Receives request to start a	Request to start TCP session with IP address and TCP
ATDT ipaddress:TCPport#	TCP session. CONNECT	port number of the Digi device server-Digi device server
	115200.	starts a TCP session
		Escape sequence is sent <P> is Pause in seconds with
<P>+++<P>	OK	“+++” being the escape sequence in ASCII characters -
		Digi device server switches from AT command to data
		mode
ATH	NO CARRIER response sent	Disconnect AT command is sent-Digi device server
		responds with NO CARRIER

In the following table, the Digi device server receives a request for a connection.

AT Command	Digi Device Server Response	Notes
	RING	The Digi device server sends a Call Notification
		Manual (ATA) or Auto Answer (ATS0=n) response-the
ATA (or ATS0=n)	CONNECT 115200	Digi device server sends a CONNECT message when
		the TCP session is started
	NO CARRIER	The Digi device server sends a NO CARRIER message
		when the remote disconnects

Originating Calls

To send data to a Digi device server, enter the following information for your application replacing the telephone number with the Digi device server’s IP address and TCP port number. Enter the following command:

ATDT ipaddress:tcp_port#

an example is ATDT 146.135.13.5:50001

Answering Calls

The Digi device server listens on a pre-defined TCP port to receive data. When the Digi device server receives a call notification (RING) through a serial port to begin a TCP connection, it needs to reply with an ATA or a pre-configured Auto-Answer to answer the call.

Note: The TCP ports assigned to the serial ports are as follows:

Serial port 1 listens on TCP port 50001

Serial port 2 listens on TCP port 50002

Serial port 3 listens on TCP port 50003

Serial port 4 listens on TCP port 50004

Disconnecting Calls

The TCP connection disconnects by either dropping the DTR signal on the serial port or sending the escape sequence <P>+++<P> to the Digi device

Chapter 9 Modem Emulation 35