PARIS — Satellite machine-to-machine (M2M) services and hardware provider Orbcomm has come out swinging at competitor Iridium’s claims that Iridium has locked up most of heavy-equipment builder Caterpillar’s future satellite M2M business, spiriting away a major Orbcomm customer.

In occasionally blistering remarks delivered during a conference call with investors, Orbcomm Chief Executive Marc J. Eisenberg said the Iridium claims were “confusing and optimistic.”

McLean, Va.-based Iridium Communications announced May 2 that it had won a “large, multi-year agreement” with Caterpillar that Iridium Chief Executive Matthew J. Desch said “establishes us as their primary provider of satellite M2M services.”

Desch said the Caterpillar (CAT) deal is “a watershed” event in Iridium’s M2M business.

Eisenberg did not wait for investor questions to attack the issue during Orbcomm’s May 9 investor conference call.

“For the immediate future, CAT has tens of thousands of Orbcomm hardware [units] in backlog and tens of thousands more still being manufactured. This represents over two years’ worth of future deployments,” Eisenberg said. “Over the next two years, we do not anticipate any material change to our CAT business. [W]e are not aware CAT has made any decision to transition away from Orbcomm on the product lines we serve in the near future.”

Eisenberg conceded that as a customer forced to make decisions among suppliers that need to launch new satellite constellations — this is the case for both Orbcomm and Iridium — Caterpillar logically would seek “to hedge their bets.” But he said he is not aware of any competition for Orbcomm-compatible business that Rochelle Park, N.J.-based Orbcomm has lost or that Iridium has won.

As to Caterpillar’s long-term plans, he said, “I don’t think anyone knows. I don’t think Iridium knows. I listened to [Iridium’s] earnings [call] and their conversation, and I’ve got to tell you it was confusing and optimistic.

“I mean some of the words they used. I’ve known CAT for 12-15 years and they don’t do things like guaranteed contracts. So when someone says they have a large contract, I don’t know what a large contract means. Does it mean a contract with a large customer? I didn’t see an 8K [a required stock market advisory], did you? Does it mean [the contract] was done on a poster board? Is that a large contract? Does it mean a large guy? I am not quite sure.

“What is a primary provider? CAT doesn’t sign you to be a primary provider, they sign you to have the ability to sell your product, and that’s it.

“Watershed agreement? I don’t even know what a watershed agreement is. So I think they are overly optimistic and they are confusing the market. I understand the pressure they are under. Their business has been contracting for many quarters now.”

Eisenberg said it is possible that Iridium won a Caterpillar contract to provide a high-usage network that was more than Orbcomm could provide but concerned no more than several thousand units. “It’s not a particularly big contract,” he said. “We were a no-bid on that and I am guessing that is probably one of the wins at our competitor.”

The importance of Caterpillar to Orbcomm is clear in the company’s May 10 filing to the U.S. Securities and Exchange Commission. For the three months ending March 31, Caterpillar accounted for 25.4 percent of Orbcomm’s total revenue, compared with 18.5 percent a year ago.

Orbcomm said 33.6 percent of its accounts receivable as of March 31 were with Caterpillar.