[Synopsis]
Call agent callback login

[Description]
  AgentCallbackLogin([AgentNo][|[options][|[exten]@context]]):
Asks the agent to login to the system with callback.
The agent's callback extension is called (optionally with the specified
context).
The option string may contain zero or more of the following characters:
      's' -- silent login - do not announce the login ok segment agent logged in/off

The 'show application' command is deprecated and will be removed in a future release. Please use 'core show application' instead.