Another competitor has been added to the area’s telephone mix, as Charter Communications rolls out local and long-distance service for cable TV and Internet customers in Hollis and Brookline.

“About half our customers, within the first year or two, end up switching over to us for their telephone service,” said Dennis Jerome, director of Marketing New England.

Charter just started offering phone service here and so far “has close to about 100 orders in the pipeline” from its New Hampshire customers. It has about 6,000 customers in Hollis and Brookline, its only service area in Greater Nashua.

It already offers telephone service in most of its national network, Jerome said. Charter is the nation’s fourth largest cable company, with 5.2 million customers in 25 states.

New Hampshire is relatively late to Charter’s telephone service because the company has a small footprint here: Just Hollis and Brookline, using service lines coming up from central Massachusetts where it is dominant, and the three northern towns of Bath, Haverhill and Piedmont, connected to its network in Vermont’s Northeast Kingdom.

One of the most complicated parts of creating such an arrangement is the inter-connect agreement between the cable company and the local phone company, necessary for calls to feed into the overall phone network.

In fact, Jerome said Charter is still working through an agreement for customers in Hollis’ southeastern corner, who are connected to FairPoint’s center in Nashua.

Comcast, the state’s dominant cable provider, has long had telephone calls as an option in its bundle of services. They are part of a national trend, as landline voice service shifts from copper telephone wires to cable-TV lines.

As of 2010, according to state figures, FairPoint had about 250,000 telephone access lines in New Hampshire while Comcast had about 203,000. This difference is likely to have shrunk since then.

In most of Hollis, Charter doesn’t compete with FairPoint. Except for the small section of southeast Hollis near the Nashua line, the town’s telephone company is TDS – a historical legacy dating to the 1920s, when Hollis did not joint the then-new AT&T monopoly but kept an independent Hollis Phone Co.

Hollis and Wilton are served by TDS, a Wisconsin-based firm that has bought scores of small, independent phone companies around the country, including the Hollis and Wilton companies. Brookline is a FairPoint town.

The Charter phone service requires a technician to visit, to hook the cable network up with the phone system, so that the existing telephone can still be used. The existing telephone number can be kept, as a result of federal mandates.

The phone service can be purchased separately, or added to TV or Internet.

The highest “off-the-rack rate” for unlimited local and long distance, including Canada and Hawaii, for people who don’t have TV or Internet already, is $44.99 a month, not including taxes and fees, Jerome said. Promotional rates are as low as $29.99 a month for a year.

There is also an installation fee for non-Charter customers of $49.99.

As with other non-telephone-line services, Charter needs a electric power to run, which means the phone service dies during power outages unless there’s a separate battery supply. Traditional phones draw power through their connection from battery packs in phone offices, and work through most power outages.

David Brooks can be reached at 594-6531 or dbrooks@nashuatelegraph.com.