How can I get my engineers to accept being on call?

Corporations; don't look for handouts, pull yourself up by the bootstraps.

Also corporations; please donate additional work for free to provide us larger margins, we're relying on your good nature for this.

You want me to be on call? Pay me.... A LOT.

I know the conversation is on another site, but I have an account here, not over there.

The CTO is an asshat and the project manager should talk to HR and a company lawyer, as others have pointed out, because of the legal binding contract the employees signed when they were hired that said nothing about being on call.

You then don't force all your engineers to be on call--forcing people who tend to be introverted and on the spectrum are usually better not talking to clients--but offer a bonus to those who agree to be on call.

we had following agreement at my last employer (small team of system engineers, agreement was implemented while I was already working there): 600.- per week you where on call. if you got a call, it was just like working overtime. if you needed to call a coworker, who was not on call, he would get a financal compensation. those who didn’t want to be on call, didn’t need to be. but it was quite chill. I don’t think I ever had a call :P

but you needed to be prepared. if I left home, I did so always with my notebook with me. I couldn’t to what I want during that week, just in case …

not compensating your employees at all for their loss in personal free time is just a real duche CTO move.