You want to connect to your Head Office through the PTSN network (or any communication network) via modem. Your main office has a broadband connection and you would
like to connect to the Internet. The
EtherPAD Duo's Routing and PPP features or
PocketPAD Router is ideal for this scenario.
The Router is placed on the LAN (Local Area Network) to which the Broadband connection serves. Once configured for dial-in access, you can connect from any remote site.
You can also gain access to the hosts connected to the LAN.
Transmitting data externally requires some sort of proxy or NAT (Network Address Translation) server to route traffic back the your PC. You could use Microsoft's Windows
Internet Sharing tool if you connect via a Broadband modem connected to the serial/USB port. Most Internet gateways/routers offer enough functionality to easily configure
this setup.
If used as a Gateway to the Internet, the Router will dial out to the ISP (Internet Service Provider) should it have any data to send. The Router can be configured for
both Dial-in and/or Dial-out modes.
With another Router at the remote site, you will be able to connect two networks together via modems. The modems need only support standard AT command set. The medium could
be anything from copper (POTS/PTSN) to wireless (DSSS/FHSS) to radio to GSM/GPRS. IP packets are routed from the PPP serial interface through the Router onto the Ethernet
network.
The Router provides a cheaper alternative to other router implementations (where the specification outweighs it's function). It can also be reused in many other applications.
You can turn off the Routing and/or PPP functions and employ it as a normal serial to Ethernet converter (i.e. EtherPAD Baseline).
