Nimans has splashed out £12.45m to acquire Rocom from the ATC group ending months of uncertainty over the future of the voice distributor.
Question marks have been hanging over the future of Rocom since last autumn after ATC Group indicated it was prepared to spin off the distribution business.
Julian Niman, chairman of Nimans, said that the chance to acquire Rocom was a "once in a lifetime" and it would make it a much more powerful player in telecoms distribution.
"It represents a real statement of intent and demonstrates our commitment to, and confidence in, the telecoms distribution market. We are a financially secure company with the strength to expand and move further forward," he said.
It will be business as usual for both companies but the current managing director of Rocom Richard Carter will stay on for three months before taking another role in the ATC Group.
Niman said that the merger would benefit the channel because there would be less energy spent in direct competition.
"As there will be less direct competition between the companies we can fully focus on channel development, rather than 'shifting' the channel where customers can get caught between the two with trapped loyalties," he said.
Last November, the ATC Group told the market that it had received "unsolicited potential interest" in one of its subsidiaries, widely believed to be its comms and network services distributor Rocom.
"Since that time, interest from additional parties has been received and the group has made significant progress on this possible disposal," ATC said in a statement.
In the most recent set of filed accounts for Rocom to the year-ended 31 December 2007, revenues grew 45.9% to £48.6m and retained profit rose to just over £2m compared to £515,000 a year earlier.