How does 'W' work?

[DRNewcomb]

Originally Posted by rfranzq

I think this question is most appropriate in the international section.

Not sure there is a section for this.

Is this how it works on all phones?

All phones I know of. There was something similar on USR modems except that "W" waited for another dial tone. When the phone sees the "P" or "W" it shifts to DTMF dialing.