The Grandstream UCM series phone system has been an industry disrupter since they first day of release. Warren Business Phone Systems have been right there with the best features, leading this charge in selling and servicing these IP PBX systems for years now! With voice over internet protocol (VoIP), hosted VoIP or unified communications as well as UCAAS services available through our managed solution – it’s hard not finding a business that can use some help from us.. Give us a call today so we may discuss how your company will benefit off one simple phone upgrade at no cost on existing lines