There are lots of different types of monitors on the market now. There are Wireless Indoor/Outdoor Intercom systems, Internet Monitoring Camera Systems, and Wireless Movement and Sound monitors.
Intercomsonline.com have different types of alarms to choose from:
Their phone number is 888-298-9489
http://www.intercomsonline.com/Wireless-Intercom-Elderly
Assistive Technology Services is another resource that can help you find an Intercom Wireless System
The phone number is 615-562-0043
http://www.assistivetechnologyservices.com