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USWD500 User’s Manual Version 3.0
- 29 -
Data Transmitting and Receiving Under UDP Protocol
The USWD500 Modem provides UDP protocol in its protocol stack. You can send
and receive UDP packets from the Internet. Before using UDP, make sure that the
modem’s network status is
CONNECT
. Re-issue the
AT!D
command. The first
three characters of the returned string should be
RCI
.
After connecting the USWD500 Modem to the CDPD network, you must enter the
ON-LINE Mode for data transmitting and receiving. Use the following command to
set the remote IP address and the port number for UDP.
For example:
ATD203.67.40.248/7;
set remote IP address and port number for
UDP
CONNECT
the network status
ATO
enter the ON-LINE mode
test-test-test-test-test
send out UDP in packets
test-test-test-test-test
receive message echoed from the remote
host, if the UDP echo service is running.
+++
leave the ON-LINE mode
When Will the USWD500 Modem Send Out Queued Data?
Buffer full
When the transmitting buffer of the USWD500 Modem is full, the modem
automatically sends out the data queued in the buffer. Simultaneously, the
USWD500 Modem sends a
CTS high
signal to the host indicating that the modem
is
not
ready. After the data is sent, the modem returns a
CTS low
signal to the
host indicating that it's now ready and the data can again be sent.
S50 Time Out (Data Forwarding Idle Time Out)
The automatic transmit control function can be enabled or disabled by the user. If
you enable this function using the
AT\T1
command, you also need to set
S50
with
the
ATS50=
t
command (where
t
= 0 ~ 255). Then save the register value (
AT&W
)
and reset (
ATZ
) the modem to restart the connection. Therefore, if the USWD500
Modem waits for more than the
S50
time period and does not receive any more
data or data forwarding characters, it will automatically send out the data queued
in the transmit buffer.
Содержание USWD500
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