TextNow - TextNow is a mobile virtual network operator (MVNO) that provides a free phone service to users by using other cellular networks coverage.
ShoreTel - Cloud phone system & contact center software & services
TextMe - TextMe is a free calls and messaging application at both local and international levels.
CorvisaOne - CorvisaOne is another cloud-based communications suite that is specially designed for companies that need features for managing inbound or outbound call centres.
Talkatone - Android App on. Google Play. Stop paying for cell minutes, texts & landlines; Turn your iPad or iPod touch into a phone; Call/Text even in areas with bad cell coverage; Call/Text when travelling without paying for expensive international minutes.
8x8 X Series - X Series connects teams across channels and around the globe, giving you access your most critical information securely, from any location.