Tara Burns, prosecuting, said 61 messages were sent from Shortall's phone to the teenager, but the DPP accepted pleas to five charges.
The gardai were satisfied that some of those 61 messages were crude jokes that Shortall had forwarded in a group message.
Garda Kevin Lynn said Shortall and his partner, Colin Huggins, had befriended the young boy and his family a number of months previously.
He had been sending the messages to the boy for just over a month when a friend of the teenager noticed them and told the boy's mother. The gardai were alerted in February 2011 as was the HSE.
Gda Lynn agreed with Ms Burns that "nothing further arises" from either the garda or the HSE investigations.
The boy told gardai he had asked Shortall to stop sending the messages.
Shortall was arrested in May 2011. He told garda that some of the texts were just banter.
The five texts contained obscene sexual suggestions.
Judge Mary Ellen Ring told Keith Spencer, defending, that she would give his client "the benefit of the doubt" as to why he formed a friendship with this boy and his family in the first instance.
She said she understood banter between 15-year-old boys, but Shortall was considerably older, which was worrying.
"This kind of behaviour puts children and young people in a very difficult position to stop the person sending the messages and makes it difficult for them to tell someone," the judge said.
She adjourned the case to April, remanded Shortall on continuing bail until that date and ordered a probation report.
Mr Huggins told Mr Spencer that he and Shortall had been in a relationship for 12 years and there was no question of his partner being interested in children or younger men.