Phone calls that pretend to be coming from a different number, a sneaky practice often used in phone scams and sometimes used by telemarketers, would be subject to civil penalties under a proposed new state law.

The bill, which was passed by the House and is being considered by the Senate, would make it illegal for calls that are made by robocall machines or done “for solicitation” to do what is known as number spoofing, or showing an inaccurate phone number to the recipient. Those convicted of it could face civil fines of up to $5,000.

Number spoofing is often used in phone scams to fool people into thinking they are talking to somebody trustworthy.

“This is something that is causing a lot of victims across New Hampshire and the country,” said Rep. David Luneau, D-Hopkinton, the main sponsor of the bill, House Bill 577.

“It not only goes at the most traditional caller-ID scams – pretending to be the IRS or the sheriff and they want you to wire money and get your nephew bailed out, that sort of thing – but to really unscrupulous ones, where it’s automatic,” said Luneau.

That refers to a new variant called the “one-ring scam.” Criminals call random numbers and hang up after one ring; the curious recipient, seeing that the call seems to have come from an innocuous-seeming number, calls back and is charged large fees because the number is actually overseas or is a premium number that racks up per-minute costs.

One-ring scams have become so widespread that the Federal Communications Commission issued warnings about it last week.

The bill is before the Senate Commerce Committee. Nobody spoke against it at a hearing on May 7.

“This doesn’t only apply to scammers. It also could potentially apply to legitimate telemarketing operations that in an effort to convince people to pick up the phone, using spoofing,” said Brandon Garod, an assistant attorney general in the consumer protection bureau. “The idea is transparency for people who own phones. You should be able to believe that if you look at your phone you are seeing accurate information.”

The issue of number spoofing has been much debated in federal telecommunications circles. It hasn’t been outlawed partly because for technical reasons it is difficult to prevent number spoofing on telephone systems and partly because there are times when it serves a legitimate purpose.

The New Hampshire bill would apply only to solicitations and to calls made with automatic dialing machines. Individuals doing number spoofing, which can be done with some smartphone apps, would not be affected.

Even if this bill passes it may not have much of an effect on scammers because it is difficult to figure out the real source of calls that have been spoofed.

“The technology is very complicated, and the majority of the time the calls are coming from overseas,” said Garod.

Even so, he said: “We encourage people to report all instances of scams. It raises public awareness of what scams are happening; if somebody gets a similar call, they’ll be tipped off this is a scam.”

Garod noted that scamming is already illegal under New Hampshire “theft by deception” laws. This bill would add a penalty for using number spoofing.

The bill is more likely to stop legitimate businesses, political parties or polling operations that are doing telemarketing campaigns from spoofing numbers to increase the chance of getting through.

Because it crosses state lines, telecommunications is the legal purview of the federal government. However, states can enforce their own consumer protection laws.

“We do it under consumer protection. We’re not preventing anybody from doing (spoofing) but we’re making it possible for the attorney general to go after them,” said Luneau. “It also gives the consumer, if they do their own investigation, identify who it is ... the ability to do it under the right of private action.”