Zaptel "4" key is out of tune

My Asterisk dials some numbers OK, but none that includes a “4”. (The phone company responds with a doo-doo-doo-doo, doo-doo-doo-doo tone that reminds me of outer space.)

When I listen in on another handset, I hear the dialing. There is something clearly wrong with the “4”. It sounds less rich and wonderful than a true “4”. It is only half there.

This is a new installation of Zaptel and Asterisk. I built zaptel/branches/1.4 and asterisk/branches/1.4 on Linux x86_64 x86_64 x86_64. When Asterisk starts, it says, “Asterisk SVN-branch-1.4-r99187”.

Please advise.

zaptel.conf says:

loadzone = us