While that was happening people in the office were trying to find out where the text came from, which we managed to identify came from our early notification system provider School-links.
"They were testing or demonstrating their product and did a test text and my secretary was still on their test list."
Mr Campbell, who was away from the school when the incident happened, said he "wasn't particularly happy" the school had received the text and was going to contact the company for an explanation.
He said the school uses the company to link with its student management system - primarily an early notification that enables the school to get in contact with parents quickly around pupils who are absent from school or where the school doesn't know where the pupil is.
"It also has features, such as, pushing out notices like we received - you can send a text to all your staff saying there is an armed intruder on the school grounds and the school is in lock down.
"They were obviously doing that with a new client or prospective client, or...but we received it."
Mr Campbell said the school was able to get messages to parents quickly, via the school's new app, as well as bulk emails and bulk texts, saying everything was okay.
He said police congratulated the school on its handling of the situation.
"We did the right thing, and you can't take any chances, but it's frustrating we received a text from an organisation that is supposed to be working for us."
He said it was an interesting learning experience for the school in terms of managing communications.
"We've learned a few things and will use them going forward - hopefully we will never have to apply them."
A spokeswoman for School-links said the company was "very aware" of what happened and was investigating what had happened. "We are looking into it."
