Polycom ViewStation manual Crypto Resync

Appendix C V.35 Technical Information

Crypto Resync

If a cryptographic encoder/decoder is connected between the ViewStation and the network, it may require a resynchronization signal from the ViewStation. This is a signal indicating that the ViewStation has lost video synchronization due to a network problem and requires that the cryptographic encoder/decoder resync with the equipment at the other end of the connection.

To enable this feature select System Info > Admin Setup >

Security. When you select the Crypto Resync option, the Crypto

Resync Pulse screen appears.

On this screen, you can enable crypto resync, set the time between pulses (in seconds), and set the pulse width (in milliseconds).

If the ViewStation is in a call and it loses H.320 synchronization, it continuously sends the resynchronization pulses at the specified rate with the specified pulse width until H.320 regains synchronization.

The resync pulse is output on the Ready-To-Send or RTS signal. If this feature is enabled, the RTS signal no longer functions as the RTS signal. Most installations that use encryption equipment require a custom cable. The cable should be designed to route the RTS signal from the ViewStation to the appropriate resync input on the encryption equipment. The encryption equipment can get its RTS input from the ViewStations DTR output or by wiring this input to an always-high tie-off. In this nondialed mode, the DTR output and RTS output act exactly the same. Refer to the V.35 State machine descriptions in this appendix for more information on these signals.

© Polycom, Inc. 199 ViewStation User Guide