Phones with Pulse and Tone Capabilities

[mwplefty]

I was at the Church rummage sale, and I picked up an AT&T white desk telephone modeled after the 500. It has the typical 12 buttons plus Re-Dial and Mute buttons. I've used this exact phone before, but I've never owned one. When I tried to dial my cell phone number as a test, I couldn't dial out. I kept hearing pulses as I hit each number. As you all know, I have U-Verse and can't use phones that pulse dial. Well, I was confused that a touchtone phone was producing pulses. I thought that I had just wasted a whole $2. About a minute later, I realized that the TT/OP switch allowed me to change from pulse to tone. It was set at OP when I got it. I switched it to TT, and it worked perfectly. My question is: why would a non-rotary phone (which is relatively new) give you choice of either dialing with a pulse or with a tone?

[poplar1]

One reason is that not all lines (until recently in any case) were programmed for Touch-Tone; there was an extra charge for it.  Until the 1980s there were some areas where Touch-Tone wasn't even offered because of limitations in the electro-mechanical equipment. And at some point even if you were leasing a phone from AT&T, they no longer stocked rotary 500s, Princess sets, or Trimlines; so they had to have phones that could switch from Dial Pulse to Tone for customers who didn't want the "luxury" of tone dialing.