Aclara, a mid-sized smart metering player that got a bit bigger when it bought GE’s metering business in November, has now added grid sensors and software to its portfolio. On Thursday, the St. Louis-based company announced it’s acquiring the smart grid business of Tollgrade, a Pittsburgh-based company working with utilities on three continents.

Terms of the acquisition weren’t disclosed. Tollgrade, which got its start as a telecommunications technology startup, will retain a portion of its business, and the press release noted that the sale will allow Tollgrade to “focus on its traditional broadband business.”

What Aclara bought is Tollgrade’s LightHouse distribution monitoring platform, which combines the company’s communications gear with a set of proprietary sensors that measure voltage, current, and other key metrics on distribution grid circuits. It's being used by utilities including Duke Energy in the United States, Toronto Hydro in Canada, and Western Power Distribution in the U.K

Tollgrade fits into a class of companies like Sentient Energy, PowerSense (now owned by Landis+Gyr), GridKey, Awesense, and others that specialize in this field. But it also competes against the grid majors like Siemens, S&C Electric Company, Toshiba/Landis+Gyr and General Electric/Alstom, which provide the same type of gear, as well as the software operating systems to run them.

With the acquisition, Aclara intends to bring the LightHouse platform to utilities as an “economical alternative to other systems” that do similar jobs, Allan Connolly, Aclara’s CEO, said in Thursday’s statement. But as Tollgrade VP Erik Christian noted, the company has been looking at a broader set of uses for its core technology as "a multi-application distribution monitoring platform, enabling them to run their network in a proactive and ultimately predictive way."

Aclara didn’t provide details on how it intends to integrate Tollgrade’s technology with its own smart metering business. It’s worth noting, however, that we’ve seen other strategic relationships between metering and sensor companies, built around an integrated platform. One notable example is Silver Spring Networks, one of the world’s biggest smart meter networking providers, and Sentient Energy, whose power line sensors have largely been deployed in conjunction with Silver Spring deployments.

“Tollgrade's strong, established relationships in the investor-owned utility market [complements] Aclara's leadership in the cooperative and municipal electric markets,” he added. The bulk of Aclara’s business in the U.S. smart metering landscape is with small to mid-size rural electric and municipal utilities.

The independent grid sensor and networking business hasn’t necessarily been an easy one. One contender, OptiSense, filed for bankruptcy in 2014 after problems with its unusual, optical-based sensor led to cancellations of utility contracts. Another, GridSense, was sold by its owner Acorn Energy to Franklin Electric Co. last month, two months after Acorn, which bought the company in 2009, announced its plans to liquidate the business