I'll call back at a more convenient time.

在方便的时候我会回电话的。

《牛津词典》

Forget the lag time of email or waiting for a call back.

不再需要无止境地等待电子邮件或者是电话回复。

youdao

Synchronous calls can be programmed, but with timeouts so that if the call can't come back in a certain time, the calling Web service can be unlocked to exit from the system.

同步调用可以通过编程来实现，但带有超时设置，如果调用在一定的时间内未返回，调用Web Services可能取消锁定，从而从系统退出。

youdao

During busy periods the call handler will agree a time for an adviser to ring back, within a three-hour timeframe.

BBC: NHS Direct Wales 'turned off' for 999 calls, Unison claims