>> Can you envision a situation where a SLK session would take
 >> place under those conditions?

 > JH> Yes. When the remote considers SLK a more desireable
 > JH> option than ZMO.

 > 'remote',  is  that  the  calling  or  answering  system?

If the caller sends

    ZMO,SLK

and the remote (receiver) wants SLK, it'll select SLK.

If the caller sends

SLK,ZMO

and the remote (receiver) wants ZMO, it'll select ZMO.

 > Since protocol selection is caller-driven, I'll assume you
 > meant caller.

How is it caller-driven? The receiving system will pick the protocol it
prefers, from the list presented by the calling system.

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