dialerf chip NTE1691

[skimask]

To my surprise they(any dialer chip) are very rare

Don't know much about the nte1691, but, you know, the PIC and PBP can be very effectively used as a dialing tone generator, as well as an effective keypad scanner, all at the same time, all packed into an 18 pin PIC.
A quick look in the PBP manual shows that FREQOUT can easily produce 2 frequencies, and the BUTTON command can check individual switches, or there are more than a few keypad scanning routines here on the forums.