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.