Is it recommended for the Project Manager to have technical experience in the industry?

As per my understanding it is not mandatory to have technical experience for the role of Project Manager however I will still recommend to have a understanding of technology. The Project manager act as a connection between Technology and Business, thus must have a basic understanding of both the worlds. Also, Project Managers with Technical understanding will have additional benefits while communicating with the technical team. For more info, about PMI courses and certifications, visit https://www.netcomlearning.com/vendors/pmi-training.phtml?advid=1356

It is not compulsary to have technicla knolwedge from the industry for Project Manager, but it will have additional benifit to executing project, if it is in technical sector.

Yes having a technical background or domain knowledge always helps to understand the complexity , challenges and hands on experience allows the project manager to successfully overcome those barriers. Having a fair technical experience helps the manager to be good mentor and lead the team effectively 

If you have technical experience ,it's highly appreciated , could avail expert power . However it's not mandatory for the project manger to be technical . He must have integration approach. If you are working in telecom industry , I would recommend to go for some basic certification to have an idea of technology . 

Not necessarily. As a project manager, you do not need to be an expert in the technical details of the type of project. You will have expert subject matter in each major activity in the project. You only need to know how to manage, how will you get the required information in the correct time and cost. 

You ll have to define technical knowledge first. it is a must for the project manager to know the vocabulary of the specific industry but without the need to know every single little terms.

Saying that, you have what you call 'transferable skills' meaning that regardless of the sector or industry, some skills/notions are universal to project management.

yes it is better off to have some technical experience and idea in the industry that you work for