I don't believe Maxima supports this.
You can, of course, always write
ibase:2$
101/10 => 5/2
101/10,float => 2.5
101*10^-1 => 5/2
101*10^-1.0 => 2.5
Note that if ibase=2, digits above 1 are not allowed in integers. But
they are allowed in numbers with decimal points:
101 * 10^-2 => treats "2" as a symbol, not a number
101 * 10^-2. => 5/4
101 * 10^-2.0 => 1.25
> How do I convert between binary and decimal in Maxima?
> For example, I would like to input 10.1 binary and get 2.5 in
> decimal. I tried playing with IBASE and OBASE but I was
> only able to convert integers.
Unfortunately, there are some bugs with ibase other than ten. (See bug 1156041)
-s