3080/V24
124001UA
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Anti-streaming
A typical problem often encountered is a
“STREAMING” remote terminal. The streaming
problem can tie up an entire circuit until the offending device has recovered or is powered
down. A streaming condition occurs when a Sub-Channel remains active, disrupting the
polling sequence. The 3080/V24 (CTS DSD-8) provides two user selectable modes of
controlling a streaming condition, an automatic anti-streaming Abort Timer with eight
selectable block lengths and a setting to disable anti-streaming for large data block transfers,
and a manual Operator Control mode (front panel push button switch).
Automatic Anti-streaming - Automatic Anti-streaming will block the asserted control signal
from the Sub-Channel Port, releasing the 3080/V24 (CTS DSD-8) to accept requests from any
other Sub-Channel that has not been locked out due to a streaming condition. When a Sub-
Channel is locked out for streaming, a visual indication, by Sub-Channel, is provided on the
front panel.
Any data sent to the Master Port by the streaming device will be lost, but data
will still be broadcast to locked out Sub-Channels. Once a Sub-Channel is locked out due to
streaming, the Sub-Channel will remain locked out until the attached device removes the
streaming condition. When configured for “Switch on RTS” Mode, if RTS is held active, RTS
must become inactive. When configured for “Switch on Data” Mode, if continuous data
transitions have triggered the Anti-Stream logic, the transitions must stop before the DSD-8
will clear the Anti-Stream logic to that Sub-Channel. Removing the Sub-Channel via the front
panel disable switch will not clear the Anti-stream logic for a Sub-Channel once it has been
activated.
Manual Anti-Stream - If manual Anti-Stream protection is chosen, a streaming condition
caused by one of the attached terminals can be quickly corrected by the 3080/V24 (CTS
DSD-8) via the associated front panel locking switches. A switch is provided for each Sub-
Channel and permits the rapid removal of a streaming terminal without having to disconnect
any cables or power down the offending terminal. Terminals may be selectively removed for
self-test and maintenance without affecting the remaining Sub-Channels. Once the streaming
condition has been corrected, the front panel switch is simply depressed to the locked
(Enable) position (Green indicator ON) to re-establish normal operation. Removing a Sub-
Channel with the front panel switch will block data from the Sub-Channel going to the Master
Port but will not block data going from the Master Port to the Sub-Channel.
Channel Selection Modes
The 3080/V24 (CTS DSD-8) provides two selectable Sub-Channel service modes of
operation, the Scanning Mode and Priority Mode. Depending on system requirements, either
mode may be selected by internal DIP switch settings. Both modes switch on activity from the
Sub-Channel.
