extraneous ^A^B in ipython within emacs shell

[kj]

Hi.  When I run ipython within the emacs shell, the ipython prompt
shows some extraneous characters; it looks like this:

^A^BIn [^A^B1^A^B]: ^A^B

...instead of like this:

In [1]:

The prompt is supposed to have a special color (and in fact, it
appears with the expected color under the emacs shell); I imagine
that this coloring probably has something to do with these unwanted
characters.

FWIW, the TERM* variables are set to:

% printenv | grep TERM
TERM=dumb
TERMCAP=


I'm running all this in OS X (Snow Leopard), and the version of
Emacs is 23.1.1.  The problem appears whether I run emacs under
X11 or with the -nw option.

Also, FWIW, I just installed this version of ipython that has this
unwanted interaction with the emacs shell; the previous version
did not have this problem.  Lastly, this ipython displays fine if
I run it on a Terminal window rather than an emacs shell window.

TIA!

~kj