I want to install a toilet in the basement on the floor onto a 5"dia.cover in the floor.In this room which is

directly below the first floor powder room.Back to the basement room,the waste pipe from upstairs comes straight down into the floor.just before the floor there is a cleanout about 8"from the floor on this pipe.this is located by the side of the house wall;adjoining wall in a townhouse.If you draw a diagonal line on the floor from waste pipe to the cap or cover 4`9" o.c.which is 16"o.c.from the front wall of the basement wall.Is this a rough in for a toilet?If so what do I do to add a vent?I know that this is not sump pump location,the cement floor is all around this cap or cover flush to the floor.I do not want to put in a subfloor.Also I ume that allthe other plumbing in the house which is near the back is routed to this cap before exiting to the out side waste line.Note the cap or cover has a square indentation in the centre.Once again I know this is not sump tank location. I would like to do as much of the work myself so details on this would be more appreciated than points