Specifications

Chapter 17 – TCP App AT Commands
100 Multi-Tech Systems, Inc. CDMA C1 AT Commands Reference Guide
0 Stop TCP/IP stack
1 Start TCP/IP stack
2 Configure TCP/IP stack
4 Save/Restore Configuration to/from NV memory
<optnum> when <mode> = 2
0 Default TTL of outgoing data grams. This option is a limit on the period of time
or number of iterations or transmissions that a unit of data can experience
before it should be discarded. The time to live (TTL) is an 8-bit field in the
Internet Protocol (IP) header. It is the 9th octet of 20. Its value can be
considered as an upper bound on the time that an IP datagram can exist in an
internet system. The TTL field is set by the sender of the datagram, and reduced
by every host on the route to its destination. If the TTL field reaches zero before
the datagram arrives at its destination, then the datagram is discarded. This is
used to avoid a situation in which an undelivered datagram keeps circulating in
the network. Valid range is 0-255. The default value is 64.
3 Number of bytes of initial TCP window. This option is used to specify the
number of bytes in the initial TCP window. A TCP window specifies the amount
of outstanding (unacknowledged by the recipient) data a sender can send on a
particular connection before it gets an acknowledgement back from the
receiver. The primary reason for the window is congestion control. Valid range is
536 to 65535. The default value is 16384.
4 Default MSS of off-link connections. This parameter specifies the initial size of
TCP segment which would be sent. Note that the TCP protocol layer will
negotiate this parameter when the socket is opened. Valid range is 536 to 1460.
The default value is 536.
6 Total number of sockets (TCP and UDP) that are allowed. This option specifies
the maximum number of TCP and UDP sockets that can be created at one
particular time. Valid range is 1 to 8. The default value is 8.
12 This option is used to specify the time from the first character received on the
UART/serial port until TCP data is sent to the network. It allows the application
to buffer TCP data before writing to the TCP socket. Note: If 536 bytes of data
are received on the UART/serial port before the timeout, the TCP data will also
be removed from the UART and written to the TCP socket.
This option value represents the number of 100 millisecond time periods to
wait. For example, setting this option to 10 will make the application wait at
least 1 second (10 * 100msec) before sending data on the IP network. Valid
range is 1 to 100. The default value is 3.
54 The UDP packet size. When the socket is opened as a UDP socket, this option
determines the UDP packet size. The valid range is 536 to 1460. The default
value is 1460.
55 ICMP Ping Reply. This is a flag which indicates if the modem should reply to the
ICMP echo request which is used by ping. The valid values are 0 and 1. The
default value is 0 which means that no reply will be sent.
<optnum> when <mode> = 4
0 Restore configuration data from NV memory. The current working TCP/IP
configuration will be overwritten with the configuration stored in NV memory.
1 Save configuration data to NV memory. The current working TCP/IP
configuration will be written to NV memory.