Title: Hardware Installation Guide.pdf
RS-485 must be terminated at both ends of the RS-485 line (bus). Terminating the line provides a more reliable communication by minimizing the signal reflection and external noise coupling. Each component provided has an on-board terminator. The installer should determine which device is at the end of the communication line.87.3Control Output WiringContact protection circuit must be used. The following two (2) circuits are recommended. Locate the protection circuit as close to the load as possible (within 12 inches [30cm]), as the effectiveness of the circuit will decrease if it is located farther away.87.3.1Relay OutputsRelay contact (DC strike)revision 6 — 421LNL-1320-U Dual Door Controller ModuleRelay contact (AC strike)DDC AUX relay wiring87.4Downstream Reader CommunicationThe DDC can communicate to two (2) card readers. The interface is six-wire that includes buzzer and LED control. The LED and buzzer are both open collector type switching (sinking) 10mA maximum.Note: