SENA PS400 - Manual (Page 40)

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4.1.7 Modem emulation mode operations
In modem emulation mode, the serial port process acts as if it is a modem attached to the serial
device. It accepts AT modem commands and answers to them, as modems would do. It also handles
the modem signals correctly. Modem emulation mode is useful in the following cases.
- There already exists a modem attached to the users’serial device.
If users’serial device already has a modem for phone-line connection, it can be just replaced by
the HelloDevice Pro Series for Ethernet connection. What users need to do is to use an IP
address (or domain name) instead of phone number as a parameter of ATA/ATDT commands.
- It is required to send serial data to the multiple remote hosts.
If the serial device should send data to the multiple hosts, modem emulation mode is required.
For example, the first data from the serial device can be sent to the first data acquisition server
and the second to the second server. What user device has to do is to change the IP address (or
domain name) parameter whenever the device sends ATD(T) XXX command.
By using the modem emulation mode of the HelloDevice Pro Series, users can have their serial device
connected to the Ethernet network easily, which is cheaper than using phone line modem. Table 4-3 is
a summarized AT command table which is supported by the HelloDevice Pro Series. Table 4-4 is a
summarized AT commands response numeric codes. Figure 4-12 shows the typical case of the serial
port command flow when ATDA command is used to connect to the Ethernet network.
Table 4-3. AT commands supported in the Pro Series
Command Internal Operation
Response
1
(Verbose Code)
+++ Return to command input mode OK
A/ Repeat last command
AT? Check status of TCP connection
If connected,
OK[CR][LF]
If disconnected,
NO CARRIER [CR][LF]
ATD(T)[remote IP]:[remote
port]
Set TCP mode as TCP client mode. And then, try to connect to
the specified remote host.
e.g. atdt192.168.1.9:1002:
Connect to IP address, 192.168.1.9, port 1002
If successful,
CONNECT [CR][LF]
If failure in connection,
NO CARRIER [CR][LF]
If other errors,
ERROR [CR][LF]
AT or ATZ Initialize TCP socket and serial port
ATA[Local port number]
Set TCP mode as TCP server mode. And then, set TCP state
as [Listen].
If successful,
OK [CR][LF]
1
If Echo mode is enabled, the command will be sent back first. And then, corresponding response will be sent. If disabled, only
response will be sent.