\begin{syntax}
telephone-subscriber  & = & global-phone-number $|$ local-phone-number\\
global-phone-number   & = & "+" 1*phonedigit [ isdn-subaddress ]\\
                      &   & [ post-dial ]\\
local-phone-number    & = & 1*( phonedigit $|$ dtmf-digit \\
                      &$|$& pause-character) [ isdn-subaddress ]\\
                      &   & [ post-dial ]\\
isdn-subaddress       & = & ";" "isub=" 1*phonedigit\\
post-dial             & = & ";" "postd=" 1*( phonedigit $|$ dtmf-digit\\
                      &$|$& pause-character )\\
phonedigit            & = & DIGIT $|$ visual-separator\\
visual-separator      & = & "-" $|$ "."\\
pause-character       & = & one-second-pause $|$ wait-for-dial-tone\\
one-second-pause      & = & "p"\\
wait-for-dial-tone    & = & "w"\\
dtmf-digit            & = & "*" $|$ "\#" $|$ "A" $|$ "B" $|$ "C" $|$ "D"\\
\end{syntax}
