Access Control , Telephone Entry, Entry Access, entry system, telephone entry systems, entry systems, telephone entry system

DoorKing manufactures a variety of access control products. These products include telephone entry systems, telephone intercom systems, card access systems, digital access systems, electromagnetic locks, high security RF access controls, automatic vehicle ID systems, vehicular gate operators, parking control products, and a variety of accessories to complete your access control requirements.
What's the difference between "Dedicated line" and "No phone Bill" access systems for multi-users?
The first requires a extra phone line service where the second costs more but uses a relay system for making connections. 

DoorKing Telephone Entry Systems
1802 Telephone  Entry System	1803 Telephone Entry System	1808 Telephone Entry System	1810 Telephone Entry System	Telephone Entry System Accessories
DoorKing Telephone Entry Systems and Intercom Systems
1883 Entry System	1834 Entry System	1835 Entry System	1837 Entry System	1812 Single User  1816 Multi User
DoorKing Access Entry Controls
Micro Plus RF Controls	Proximity Card Reader	1500 Series Digital Keypads	Stand Alone Card Readers	Magnetic Locks
Electric Door Locks	Electric Door Locks	1818 Access Control	Key Switch	Gate  Accessories