Telenetics 2185 manual Applications, Anti-Streaming

Telenetics 2185

phase, frequency, and the presence of jitter could cause the subchannel and the main channel to lose synchronization. If synchronization is lost, data errors occur and transmission fails.

When the 2185 is configured for asynchronous operation, the retiming buffer is bypassed.

Anti-Streaming

Anti-streaming protects the network from becoming jammed if one of the subchannel devices fails. If the subchannel remains active for longer than the anti-streaming time-out period, nominally 25 seconds, it auto- matically is disabled and its alarm LED indicator lamp illuminates.

When a subchannel is disabled, it disconnects from the main channel and is not permitted to contend for the main channel again until after it is re-enabled. Before attempting to re-enable the subchannel device, it must be inactive for approximately 1.5 seconds. The alarm LED then extinguishes and the subchannel can again contend for the main chan- nel. You may disable anti-streaming with a front panel switch.

APPLICATIONS

The 2185 is used in multipoint networks made up of a controller and polled terminals. The controller inserts terminal address codes and the terminals must be able to respond to their own address code. The 2185 arbitrates if two or more terminals try to transmit simultaneously.

When considering possible applications for your 2185, remember the following points:

•The 2185 can transmit in either asynchronous or synchronous for- mat, but all devices in the network must use the same format.

•All devices must operate at the same data rate. When the main channel is connected to a DCE device, the transmit and receive clocks may be at different rates, but all devices have common transmit clocks and common receive clocks.

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