Yes. If you left THAT comma out, the cable would have a look of dispair. I know that logic will tell your reader that it was he and not the cable that had a look, but other situations could be ambigous.
Mary looked at the girl, with a frown on her face. - I read this as Mary frowning, not the girl.
Mary looked at the girl with a frown on her face. - I read this as Mary looked at the frowning girl.