nextgenast ~ # equery uses zaptel
[ Searching for packages matching zaptel... ]
[ Colour Code : set unset ]
[ Legend        : Left column  (U) - USE flags from make.conf                                                                                                                                                   ]
[                  : Right column (I) - USE flags packages was installed with ]
[ Found these USE variables for net-misc/zaptel-1.2.11 ]
 U I
 - - bri          : Enable ISDN BRI support (bristuff)
 - - ecaggressive : Make the mark2 echo canceller a little more aggressive
 - - eckb1        : Use the KB1 echo canceller
 - - ecmark       : Use the MARK echo canceller
 - - ecmark2      : Use the MARK2 echo canceller (default)
 - - ecmark3      : Use the MARK3 echo canceller
 - - ecmg2        : Use the MG2 echo canceller
 - - ecsteve      : Use the STEVE echo canceller
 - - ecsteve2     : Use the STEVE2 echo canceller
 - - florz        : Enable florz enhancement patches for ISDN BRI
 + + kernel_linux : <unknown>
 - - rtc          : Use the realtime clock on x86 and amd64 systems instead of k                                                                                                                               ernel timers
 - - ukcid        : Enable UK callerid support
 - - watchdog     : Enable the watchdog to monitor unresponsive and misbehaving                                                                                                                                interfaces
 - - zapnet       : Enable SyncPPP, CiscoHDLC and Frame-Relay support
 - - zapras       : Enable PPP support for Remote-Access-Service

nextgenast ~ # equery depends zaptel
[ Searching for packages depending on zaptel... ]
net-misc/asterisk-1.2.13-r1