User guide

Part 1 – AT Commands for All Universal IP Devices Chapter 5 – TCP Commands
Universal IP AT Commands Reference Guide (Document S000457H) 39
#TCPSERV – Set Address of Remote TCP Server
Definition: To exchange data over TCP, the TCP/IP stack software must know the address of the remote
TCP server (or host) that is to be used.
Syntax: Set Value: AT#TCPSERV=id,"<Address of remote TCP server value>"
View Value: AT#TCPSERV=id or AT#VTCP=id, or AT#VALL
id: Enter a Profile Setting: 1 or 2 {1,2}
Values: Set the value that the Profile will use:
32-bit number in dotted-decimal notation (i.e., xxx.xxx.xxx.xxx) or
Alphanumeric ASCII text string up to 120 characters if DNS is integrated. No default.
#TCPTXDELAY – Time Delay
Definition: This command determines the time delay introduced before sending a TCP frame that has not
been entirely filled with user data. The time is entered in milliseconds, and it should be noted that
a value of 0 initiates the sending of a TCP frame as soon as possible after the reception of a
single character value from the host.
Syntax: Set Value: AT#TCPTXDELAY=id,<Time Delay value>
View Value: AT#TCPTXDELAY=id or AT#VTCP=id or AT#VALL
id: Enter a Profile Setting: 1 or 2 {1,2}
Values: Set the value that the Profile will use:
Integer multiple of 20 between 0 and 32760 inclusive.
Default: 0
#LTCPSTART – Open Listening Mode
Definition: This command, sent by the attached host, directs the TCP/IP stack to open a listening TCP
connection on the specified TCP port.
Once an IP link is established, the attached host can open a listening TCP socket at any time
(except when the TCP/IP stack software is already in a process using TCP resources).
The TCP connection will be active upon reception of a TCP connection request sent by a remote
allowed TCP peer (TCPSERV) on the appropriate TCP port (TCPPORT).
Once opened, this TCP connection may be closed by the remote TCP peer or by the attached
host by sending an ETX character on the serial port (depending on the DLEMODE parameter).
Notes:
The LTCP command can be aborted before an incoming TCP request has been received by
issuing an <ETX> character on the serial port.
If the DLEMODE parameter is set to 1, the TCP/IP stack will interpret an <ETX> character only as
a close request if a <DLE> character does not precede it. 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 the DLEMODE parameter is set to 0, the TCP/IP stack will never close the TCP connection
(unless an error occurs).
Syntax: AT#LTCPSTART=id
id: Enter a Profile Setting: 1 or 2 {1,2}
Values: DLEMODE
TCPPORT
TCPSERV
TCPTXDELAY