Product manual

XStream-PKG-R™ RS-232/485 RF Modem – Product Manual v5.x00
SY (Time before Initialization) Command
<Networking> SY Command keeps a
communication channel open as long as modem
transmits or receives before the active connection
expires. It can be used to reduce latency in a
query/response sequence and should be set 100
ms longer than the delay between transmissions.
This command allows multiple XStream Modems
to share a hopping channel for a given amount of
time after receiving data. By default, all packets
include an RF initializer that contains channel
information used to synchronize any listening receivers to the transmitter’s hopping pattern.
Once a new modem comes within range or is powered on within range, it is able to instantly
synchronize to the transmitter and start receiving data. If no new modems are introduced into
the system, the synchronization information becomes redundant once modems have become
synchronized.
SY Command allows the modems to remove this information from the RF Initializer after the
initial synchronization. For example, changing the SY Parameter to 0x14 (20 decimal) allows all
modems to remain in sync for 2 seconds after the last data packet was received. Synchronization
information is not re-sent unless transmission stops for more than 2 seconds. This command
allows significant savings in packet transmission time.
Warning: Not recommended for use in an interference-prone environment. Interference can
break up the session and the communications channel will not be available again
until SY time expires.
With SY set to zero, the channel session is opened and closed with each transmission - resulting
in a more robust link with more latency.
TO (DO2 Timeout) Command
<Serial Interfacing>DO2 output will return to
default after no DI2 status information is
received during the timeout period.
Use with CS = 2 or 4.
TR (Transmit Error Count) Command
<Diagnostics> TR Command records the number
of retransmit failures. This number is
incremented each time a packet is not
acknowledged within the number of retransmits
specified by the RR (Retries) Command. It
therefore counts the number of packets that were
not successfully received and have been dropped.
The TR Parameter is not non-volatile and will
therefore be reset to zero each time the modem
is reset.
AT Command: ATSY
Binary Command: 0x17 (23 decimal)
Parameter Range: 0 – 0xFF
(x 100 milliseconds)
Default Parameter Value: 0 (Disabled - channel
initialization information is sent with each RF
packet.)
Number of bytes returned: 1
AT Command: ATTO
Binary Command: 0x31 (49 decimal)
Parameter Range: 0 – 0xFFFF (x 1 second)
Default Parameter Value: 3
Number of bytes returned: 2
Minimum Firmware Version Required: 4.30
AT Command: ATTR
Binary Command: 0x1B (27 decimal)
Parameter Range: 0 – 0xFFFF
Default Parameter Value: 0
Number of bytes returned: 2
Related Commands: RR (Retries)
Minimum Firmware Version Required: 4.22
© 2014 Digi International Inc. 38