Roles & Responsibilities or Job Description of Individual Employees in Software Company?

I am Rohini, working as "HR" in Software Company. We develop the Banking Software.
We have different level of Employees like :
1. Project Manager
2. Software Developer
3. Support Team (we have dedicated support team , which supports our clients, if they get any issue in handling the software through telephone)
4. Network Admin
5. System Admin
6. Accounts Department
7. HR department
8. Marketing Team
9. Data Migration Team
We have to give the Roles & Responsibilities or Job Description to all of them.
Request to please support me to elaborate the same.

Job Description for any unit has to come from inside. For example to wright a proper / adaptable / expected, Role and Job responsibilities, can be dome by a person, who is his immediate Manager to whom he will be reporting. Then his pier group members and last but least his immediate subordinate, about their expectation. Ask individually to write as an exercise in an training session, then compile all, you will find a ' best, adaptable roles and responsibilities' for the particular staff.
This an exercise to be done internally. No other firms roles and responsibilities of staff will certainly can not be made applicable/ adaptable, as the same would create lot of barriers for the staff to perform in his present service conditions, conditions and exceptions, which will vary from one establishment to another.
I hope I have made it clear to you. You may either do it in your training session or engage a trainer to prepare a draft based on the similar exercise and compilation of data.