[Asterisk-Users] Cell Phones and Tone Recognition

[Brian]

When I dial from a cell phone into asterisk,
I can press 1, 2, 3 etc to get to the various voicemail boxes and
menus.. that's fine.
but when I try 9-1-NXX-NXX-NXXX, i get
  -- Hungup 'Zap/2-1'

When I try the same thing from land line, everything works perfect.
BTW (setup is 2 X100P cards)

Is there any difference between the Cell phone and Land line that would
make asterisk perform differently?

Brian