Intercel Smart SAM3S User Manual - page 13
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Intercel Pty. Ltd.
A.C.N. 007 077 161
33 Glenvale Crescent
Mulgrave VIC. Australia 3170
Email :
intercel@intercel.com.au
Internet :
www.intercel.com.au
Ph : 61 3 9239 2000 Fax : 61 3 9561 2614
8. THE SAM3S TCP/IP Operation
The SAM3S has a MCU (Microcontroller) to control the 3G module PHS8-P, the SAM3S can be operating
in there different modes, defined by parameter SAMMODE:
-SAMMODE=0, modem is in dumb mode, when power on the MCU turn on the 3G module, check its
baud rate, turn on LED and release control of the 3G module to the connecting device, AT commands
can be send from serial port here after, the MCU keep monitor the 3G module Rx pin for AT$ commands
and check time in the POLLPERIOD parameter (to reset itself and the 3G module.
-SAMMODE=1, modem is in GPRS or PSD (Packet Switch Data) smart mode, the MCU is in total control
of the 3G module, on power up the software reads all parameters from flash and activates a GPSR
connection, it then creates an UDP and a TCP socket to listen for data transfer connection, opens an
UDP and a TCP socket to listen for remote AT commands connection, if programmed as TCP client it
will tries to connect to a remote TCP server, the modem then stays in GPRS online idle state waiting for
CSD call, SMS, UDP data or TCP connection, the software maintains GPRS connectivity by the mean of
IP TRACE using POLLPERIOD parameter stored in flash.
-SAMMODE=2, modem is in CSD (Circuit Switch Data) smart mode, this mode is used if SIM card is not
setup for GPRS, MCU is in total control of the 3G module, modem is always in waiting for CSD call or
SMS.
The reason for using SAMMODE=1 for PSD and SAMMODE=2 for CSD is because it is not possible to
configure the SAM3S for simultaneous operation of PSD and CSD, when the SAM3S (3G) is connected
to PSD (IP mode), the modem status is busy when one try to make a data call to it, this is the behaviour
the of the 3G network.
The modem supports DDNS, for SIM card that has dynamic public IP address the software can performs
dynamic DNS updating
to a DNS server (supporting
dyndns.com
and
noip.com
).
The modem provides security for remote management by keeping a list of SMS sending mobile numbers,
a list of CSD calling numbers, a list of PSD sending IP addresses and username and password login,
password data is encrypted for remote transaction.
8.1 Communication Sockets
TCP Data: Socket connection allows transparent data to pass through from host computer to the
modem serial port and vice versa, this operation is similar to the CSD data
communication, in TCP server mode the socket will be disconnected after 5 minutes of
no data transfer.
UDP Data: Socket connection allows transparent data to pass through from host computer to the
modem serial port and vice versa, this operation is similar to the CSD data
communication, a block of data received from a remote UDP server will open a 2 minutes
window for data to be transfer from the serial port.