Inter-compatibility of CVSD's?

I'm looking to redesign an old audio speech board, and there were two variations using either a HC55516 or MC3417 CVSD chip to synthesize the voice based on the digital data input. As far as I can find, neither of these CVSD chips are available anymore except the occasional source at $25+ per chip. They also used the same EPROM data.

I did find there is a CMX639 CVSD chip available. About half the price or better, and I have found a few sources for them. But I really don't know enough of how CVSD's operate, but I wonder if an appropriate decoder circuit may be possible to use the CMX639 in place of an HC55516 or MC3417? I don't need to do any encoding at all.

Would be open to other CVSD chip suggestions, just not finding many out there.

-Hans

Well, found an answer, and the answer is yes. The CMX639, apparently, can decode the same CVSD encoded data as the HC55516/MC3417 when set to a 3-bit algorith.

Sweet, makes my life easier for sure.

-Hans

Thanks for the info, Hans.