Comcast has been quietly deploying a primary rate interface (PRI) trunk replacement offering across its footprint since the third quarter of last year, and it's currently in place in 85 percent of the cable operator's footprint.

In an effort to move into medium-size business-class services, Comcast has been pairing its Comcast Business Class Trunks with its DOCSIS 3.0-based data service that has up to 100 Mbps on the downstream.

Comcast Business Class Trunks provide a connection between the customer's telephone system, their PBX and the Comcast network. A customer can choose to have any number of voice channels – essentially simultaneous usable phone lines – from six all the way up to 23.

With Comcast Business Class Trunks, every employee in a business has the option of using their own direct line instead of a main line with extension. As a business grows, trunks and employee phone numbers can be increased.

Since Comcast's IP network is physically separate from leased or public facilities, disruptions to other networks don't have an impact on Comcast's trunking service.

"Right now in the market you can get 100 Mbps and a full PRI for $599 a month, which is less than most companies were paying for either their PRI or their Internet, let alone the two of them together," said Kevin O'Toole, senior vice president of product management and strategy for Comcast Business Services. "That's an incredibly powerful combination."

O'Toole said a full PRI could easily serve a business with 100 employees.

"We'll be bringing out the ability to buy multiple PRIs, two three or four PRIs, for your larger sites down the road," O'Toole said. "That lets us just continue to move up market."

In its first-quarter earnings report, Comcast's business services revenues were up 50 percent over the same quarter a year ago to $364 million. Last year, Comcast had $1.3 billion in commercial services revenue, which was the first time it topped $1 billion, and it expects to increase that amount to $1.6 billion this year.

While Comcast doesn't break out where those commercial service revenues come from, O'Toole said the bulk of them were from the small business sector, which is typically under 20 employees.

Comcast has aspirations to make a bigger move into the medium-size and enterprise commercial services sectors.

"Down the road, we are looking at hosted PBX," O'Toole said. "About a year ago we purchased a company called New Global Telecom, and now we are in trial with our hosted PBX offering up in Boston and in Western New England. We also see a lot of additional upside in the Metro Ethernet space."

O'Toole said that the talent, know-how and tools from the New Global Telecom acquisition were at the center of Comcast's hosted PBX trial.