3.11 System Restrictions
(Page 12 of 12 in this chapter)
The following system restrictions should be noted regarding call control functions:
The protocol-independent call control functions can only be used when a line protocol is executing on the port.
DSP functions are only available when the line is in the connected state. There are exceptions to this rule, which are protocol-specific and are explicitly noted. For example, some protocols allow the application to generate a tone and play messages in the rejecting call state.
(Page 12 of 12 in this chapter)