options—Set the
options parameter by typing options, a Space, the option-name
audio-payload-type-mapping=yes with a “plus” sign in front of it, and then
press Enter.
If you type the option without the “plus” sign, you will overwrite
any previously configured options. In order to append the new options to the
SIP interface configuration’s options list, you must prepend the new option
with a “plus” sign as shown in the previous example.