After many years of faithful service, our TV, a Magnavox, conked out on us, and we had to get a new one. Normally new appliances are a cause for celebration, and indeed, we are now the proud owners of a Sony television with 2 more inches of screen real estate. The picture quality is also noticably better.
It worked as soon as it was plugged in, of course, but it has a wide array of features and options available through on-screen menus, and we waded through them all with glee. When we came to the close caption menu, I found the usual list of CC1, CC2, etc., SAP1, SAP2, etc. . . . but . . . but . . . where’s CC WITH MUTE?
On our old TV, you could set the closed captioning options it so that when you hit the MUTE button, it would automatically start showing closed captioning. This rocked. If the phone rang, you could hit the mute button and be able to talk to the person on the other end without totally losing track of what was happening on TV. This was especially valuable for conversations that didn’t require much brainpower, like talking to telemarketers or my MIL. 
It was also great when one of us wanted to talk on the phone and the other wanted to watch TV; the person on the phone didn’t have distracting background noise and the person watching TV could still follow the program.
This was such an obviously Good feature that it never occurred to me they might make televisions without it in this day and age! Argghh! Now what? For long conversations, it’ll be worth it to manually go into the menu and turn on the closed captioning, but I’ll miss our old TV everytime I have to do so. sigh