The push-to-talk walkie talkie-type feature of many feature phones of old may seem antiquated, but such capabilities were once highly valued by certain people and professions. Because of this, many Nextel phones were mainstays of many construction sites and manufacturing facilities. When Nextel was bought by Sprint, however, the focus quickly shifted from push-to-talk as Nextel was gradually subsumed within Sprint.

The eventual shutdown of the Nextel network contributed heavily to Sprint subscriber losses last year. Now it appears Sprint is determined to bring back more of Nextel’s most identifying feature for customers who need it.

Sprint this week announced that it will be bringing push-to-talk services to more smartphones via a software app. The “Sprint Direct Connect Now” app will now allow more smartphones to use Sprint’s “Sprint Direct Connect” service, enabling push-to-talk via a variety of devices.

Sprint is pushing its Direct Connect service as a key feature for businesses, especially in the construction, manufacturing, and emergency services industries. The company is co-promoting its “rugged, military spec” handsets along with its push-to-talk service.

The new devices capable of using Direct Connect include the Samsung Galaxy S4, Samsung Galaxy Note 3, LG G2, LG G Flex, LG Optimus F3, and Kyocera Hydro Edge. Sprint claims that the software will also soon work on Samsung’s Galaxy S4 Mini and Galaxy Mega smartphones.

Though the Direct Connect service is included in some Sprint service plans, the company is charging $5 per month for the push-to-talk service for plans that do not already include it.