Part 1 – AT Commands for All Universal IP Devices

Chapter 5 – TCP AT Commands

#LTCPSTOP – Close TCP Listening Mode

Description: This command directs the TCP/IP stack to close a TCP listening mode (previously launched by the AT#LTCPSTART command.

Syntax: AT#LTCPSTOP=id

id:Enter a Profile Setting: 1 or 2 {1,2}

Values: DLEMODE TCPPORT TCPSERV TCPTXDELAY

#OUTPORT – UDP/TCP Local Port Number

Description: Controls the local port that the UDP/TCP connection is bound to.

Syntax: AT#OUTPORT=<Port Number value>

AT#OUTPORT? Read or display the current setting (or AT#VALL ).

Values: Set the port number local connection will use: From 1 to 5 numeric digits (0 to 9).

Note: Numbers above 65,535 are illegal since port identification fields are 16-bits long in the IDP header.

Default: 37500

#OTCP – Open a TCP Connection

Description: This command sent by the attached host directs the TCP/IP stack to open a TCP connection to the specified TCP server. Once an IP link is established, the attached host can open a TCP connection at any time (except when the TCP/IP stack software is already in a process using TCP resources).

This TCP connection may be closed by the remote TCP server or by the attached host via sending an ETX character on the serial port (depending on the DLEMODE parameter).

DLEMODE Value Notes:

Depending on the DLEMODE value, the attached host may close this TCP connection by sending an ETX character.

If the DLEMODE parameter is set to 1, the TCP/IP stack will only interpret an <ETX> character as a close request if it’s not preceded by a <DLE> character. As a consequence, the attached host must send <ETX> characters preceded by <DLE> characters, and it must also code <DLE> characters in <DLE><DLE>. Similarly, each <ETX> character present in the payload data of the TCP frame will be coded by the TCP/IP stack on the serial port as <DLE><ETX>. Each <DLE> character will be coded as <DLE><DLE>. The attached host must then decode the TCP socket flow to remove these escape characters.

If DLEMODE is set to 0, the host cannot close the TCP connection (unless an error occurs).

 

If the remote TCP server closes the connection, the TCP/IP stack sends an ETX character on the

 

serial port.

Syntax:

AT#OTCP=id

id:

Enter a Profile Setting: 1 or 2 {1,2}

Values:

DLEMODE

 

TCPPORT

 

TCPSERV

 

TCPTXDELAY

Universal IP AT Commands Reference Guide (Document S000457K)

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Multi-Tech Systems iCell GPRS (MTSMC-G2-IP manual #LTCPSTOP Close TCP Listening Mode, #OUTPORT UDP/TCP Local Port Number

iCell GPRS (MTSMC-G2-IP specifications

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