USRIOT USR-N520, User Manual

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transmission mode.
Example for judgment of packaging time and packaging length:
1
Set packaging time as 10ms, packaing length as 512 bytes
When serial port received data, USR-N520 will package and send it to network if the interval time of
receiving data is over than 10ms or data length is more than 512
。
2
If the value of packaging time or packaging length is 0, the packaging rule is effective for non-zero
one.
3
Set packaging time and length as 0. USR-N520 will conduct default packaging time when
packaging time is set as 0ms. Namely, when serial port receiving data, USR-N520 will package and send the
data to network if interval time more than packaging time of sending 4 bytes. For example, baud rate 115200,
packaging time for 4 bytes is T=0.4ms, when the calculated value is smaller than 0.1ms, packaging time can
be calculated as 0.1ms.
T= 1/baud rate*10*4
3.5.9. Flow Calculation
When USR-N520 receives data from network and then send to serial port, as the limit of serial port speed,
user have to control the flow, if not the problem of data overflow on serial port side will occur. So data flow is
required to calculated when sending data from network to serial port.
Example:
Network sends data in m bytes every n seconds. Method of checking if there is overflow: ( Supposed
network condition is good and network data transmission time is negligible)
1
If there is no overflow, m bytes data must be transmitted within n seconds, then the transmitting time
of M bytes data:
If n >2T, then data will not overflow, USR-N520 can work normally. Just need keep n>T under baud rate
9600.
3.5.10. Synchronous baud rate (RFC2217)
For encryption during data transmission, devices change data bytes, baud rate, parity and so on.
USR-N520 supports revise serial parameter accordingly.