ReadyLink was a "walkie-talkie" service, which used Session Initiation Protocol (SIP), offered by the Sprint Nextel Corporation, in an effort to compete with then-separate Nextel Communications.
It was necessary to have a Sanyo or a Samsung ReadyLink capable phone and a matching service-plan in order to use this feature.
This technology will run over the Sprint high-speed EV-DO data network, giving it the closest comparable speeds to Motorola's iDEN Direct-Connect in the push-to-talk industry.
Some of the same phones are available, and Bell subscribers can roam with the service on Sprint's network.
[1] Phones with ReadyLink: This article related to telecommunications is a stub.