Hello NRV, I acknowledge your question. In the case of Nirmal Chand v. Girindra Narayan, the Court had defined the word Caveat, wherein it said, A Caveat is a caution or warning given by a person to the Court not to take any action or grant relief to the other side without giving notice to the caveator and without affording opportunity of hearing him. A summons in a caveat case is a request for the court to decide whether or not the caveat is justified and whether the caveator should issue court proceedings for the dispute to be resolved. Issuing of summons where caveat is not filed has been put light in case of Tajunissa & Anr. vs Mr. Vishal Sharma &Ors., wherein it was held that summons is not necessary to be duly issued in all and every suit. You can the below link for more information on the same
https://www.lawyersclubindia.com/news/defendant-not-issued-summons-or-present-without-a-caveat-can-be-heard-to-decide-upon-the-rejection-of-the-plaint-19183.asp
And the time to get opponents file written is the same in both the cases i.e., 30 days from the receival of summons.
I hope I have answered your question.
Have a good day.