asterisk-app-fax is uninstallable due to conflict on libspandsp1

$ sudo apt-get install asterisk-app-fax
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.

Since you only requested a single operation it is extremely likely that
the package is simply not installable and a bug report against
that package should be filed.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
  asterisk-app-fax: Depends: libspandsp1 but it is not going to be installed
E: Broken packages

$ apt-cache show asterisk-app-fax | grep Conflicts
Conflicts: libspandsp1 (>= 0.0.3)

$ apt-cache policy libspandsp1
libspandsp1:
  Installed: (none)
  Candidate: 0.0.5~pre4-1
  Version table:
     0.0.5~pre4-1 0
        500 http://192.168.1.210 intrepid/universe Packages