Patently-o provides a good summary of the steps in order to determine what a term means. Starting with the plain meaning, commodity simply means "goods" or an "article of commerce." (see e.g., Merriam-Webster supporting this plain meaning). One can argue that the analysis should stop there, however the claims and specification (while never actually using the term commodity) add context around this term. Specifically, a "commodity" in claim 1 requires a user interface, a memory, and a communication element. Thus, it's clear that this just isn't any type of "good" but a narrower type of good.
Possibly, commodity could be construed (narrowly) as a tangible good (plain meaning) having a user interface, memory, and communication element. The other independent claims all recite, more or less, these aspects. Note: memory may be too much given that claim 60 does not require memory, but that may be splitting hairs given the minor importance in the ned.
Alternatively, the specification provides grounds for a broader construction that the term simply refers to electronic, consumer goods capable of data transmission (e.g., the examples of which are telephones, fax machines, and televisions). These devices all have a UI, memory, and communications means. With this construction, commodity would also cover laptops, desktops, tablets, etc.
In short, there's no "clear" answer for claim construction most of the time. Unless the description provides an explicit "definitions" sections. What you want to do is find a reasonable balance between being too narrow and being overly broad. The patentee should not be unnecessarily forced to adopt a construction that forecloses infringement, but should not be allowed to claim protection over devices that are clearly not relevant to the claim.