The serial Ethernet gateway enables the addressing of serial end devices from the local network of the router or via the WAN interface, which are connected to the serial interface (if available). The data which is sent to a configurable network port of the router is output at the serial interface. The connection to the serial Ethernet gateway can either be maintained permanently (leased line mode) or initiated on request.
Modem emulator
The serial Ethernet gateway can emulate a modem. It provides a series of AT commands for this. A modem will be emulated for each connection type with this function. If an outgoing connection has been activated by the command ATD or ATDT , the modem emulator will always be used, even if it is disabled.
The Modem emulator is enabled in the Ports → Serial Ethernet menu in extended view using the Activate modem emulator switch.
If the modem emulator is enabled, a Default answer for unknown commands can be entered; this is returned when an unknown or invalid AT command is entered.
In addition, an AT answer list with self-defined command-reply pairs is available. Each line in this text file defines a command-answer-pair in the form i="Serial Ethernet Gateway Version 1.0". The part in front of the = specifies the command (here i for ATI; the at must be omitted) and the part behind in quotation marks specifies the associated reply (here "Serial Ethernet Gateway Version 1.0"). In this case, the message Serial Ethernet Gateway Version 1.0 would be returned upon the command ATI . A multi-line answer within the quotation marks is possible. Capitalization is ignored. Moreover, the order of the entries must be observed. If, for example, a reply for the command ATXY and one for the command ATX are defined, the entry for the command ATXY must be before the entry for ATX , because when entering the command ATXY, the entry for the command ATX would be found first and processed to look for an entry of a command ATY then, which does not exist.
Mappings for converting phone numbers to IP addresses or domain names with port specifications can be entered into the telephone number - IP address translation list. This allows for example that a connected analogue device can establish a connection to an IP address by dialling a phone number using the ATD command. The characters 0-9, + and , are permissible for the phone number. The list will be processed top-down, i.e. the first entry will be evaluated in case of identical telephone numbers.
The following AT commands are supported:
AT command | Description |
|---|---|
| Connection establishment to <IP>:<Port> or <Domain>:<Port> |
| Connection establishment to the IP address or domain that is connected to the phone number <number> in the Telephone number - IP address translation list. |
| Redialling of the last dialled connection (only possible as long as the serial Ethernet gateway has not been restarted) |
| The serial Ethernet gateway closes the serial Internet connection |
| Configuring the echo behaviour |
| Puts the serial Ethernet gateway into command mode (a pause of at least one second is necessary before and after the string) |
| Change from command mode into data mode |
| Configuring the quiet behaviour |
| Configuring the message format |
| Closes the connection |