Maxon MA-2020, Руководство пользователя

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PPP Server
Usually the Intelimax acts as an IP connected cellular serial server, relaying data
between its serial inputs to TCP/UDP sockets. Devices connect to serial port of Intelimax,
directly send data or use dial commands to set up a data transmission session. Some
devices may need to use their own TCP/IP stack, in which case either serial modem
mode (transparent) or PPP server can be used. The benefit of using PPP server over
serial modem or transparent mode is that the modem functionality can continue to be
used and it will be uniquely addressed within the system. This allows for the use of AT
over IP for sending and receiving SMS messages or querying the signal strength, SNMP
for remotely monitoring the status of the modem, or remote firmware upgrades to the
modem if required.
* PPP, or Point-to-Point Protocol, is a protocol commonly used to establish a direct
connection between two devices over a serial cable, phone line, trunk line, cellular
telephone, specialized radio links, or fibre optic links.
Gateway
In this working mode, the Intelimax will launch a PPP server and wait for the user device
PPP client to connect. Once the PPP connection is established, the device can talk to
the Intelimax through a network connection. The Intelimax then acts like a network
gateway, all data traffic from the device will be routed to the WAN interface, and then
be sent to the internet. In all PPP server modes, traffic from end-device to internet is
masqueraded behind modem WAN IP.
The device can use any TCP/UDP port to talk to peer applications on the internet side,
thus the dedicated TCP/UDP socket connection between the Intelimax and user server
application is no longer needed, the user device can open socket directly.
WAN PPP Conn
3G/4G Network
LAN PPP Conn
Serial
3G connection