Castle Square Tenants Organization has recently joined the growing netBlazr broadband cooperative network. Castle Square is located on Tremont Street in Boston, MA and has been around since 1987. CSTO is known for providing affordable housing for low and moderate income residents. Castle Square is also focused on brokering relationships between the residents and management, which helps make for a peaceful living environment. After joining the co-op, netBlazr is proud to offer CSTO a fast and reliable shared broadband service.