N O V A T E L W I R E L E S S T E C H N O L O G I E S L T D .
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A T C o m m a n d S p e c i f i c a t i o n - E x p e d i t e a n d M e r l i n
W i r e l e s s I P M o d e m s
Data Forwarding Idle Time-out
Description:
When using the internal stack either UDP or TCP, the data being sent to the modem is automatically
encapsulated in an IP packet using the preset protocol. The packet size may vary depending upon the
rate at which the data characters are received. If the data is received in a very sporadic manner, the
modem will assemble and send a packet after an idle period has elapsed, no data is received in this
interval. This keeps the data moving, retaining some time relevance instead of waiting for a specific
number or a full buffer. The modem will also send a packet if a return character is encountered in the
data stream.
The timer value is programmable from 0.1 to 25.5 seconds in 1/10
th
of a second resolution.
Format:
ATS50?
Data Forwarding Idle Time-out
General command format
ATS50=<time-out value>
Where:
<time-out value> = Time-out value in 1/10
th
seconds [0 -
255]
Example command
ATS50=15 the time out value is set to 1.5 seconds
Default factory setting is
0.5 seconds
Validity:
Other Considerations:
For most applications, data is sent in bursts, with each burst of data having relevance within the
application. To define the length of each packet, it is recommended to send the data in bursts followed by
a return. Packet length will vary as both UDP and TCP include overhead information in each packet.
Typically TCP will include a 40 byte header while UDP uses less than 20 bytes for header information.
UDP is generally used to reduce data transmission costs but requires the application to handle lost
packets and retries.
Related Topics:
