Rattigan, with a last address at Cooley Road, Drimnagh, has also denied possessing two mobile phones at Cell 42, E1 Landing, Portlaoise Prison while an inmate at the prison on May 22, 2008.
Det Sgt Robertson told prosecution counsel Sean Guerin he had worked for the Garda National Drug Unit for 15 years and that, in his capacity as supervisor, had been involved in 2,500 undercover purchases of heroin and hundreds of drug seizures over the past five years.
He said that a text message printed out from an analysis of a phone found along with five kilos of heroin in a shed at the back of the house on Hughes Road South, which spoke of "half bars," boxes" and "9" being allocated to names such as "Gangko" "McGyver" "Peck" and "Crazy", referred to the division of drugs by weight.
Det Sgt Robertson said that a "box" meant one kilo, a "9" meant nine ounces while a half bar was in relation to four-and-a-half ounces.
Mr Guerin also read to the witness a message sent to a number associated with one of the phones found in Portlaoise, which asked: "Can you give me half a box of the bad thing for 13 I am waiting on a few bob I could sort you out."
Det Sgt Robertson said it was "quite clear" to him the message was a request for half a kilo of heroin in return for €13,000, as heroin was referred to as "the bad thing" due to its known attributes and nature.
The trial continues.