Specifications

Alto 818 Installation and Operation
2-8 P/N 66109074001 Rev. D
RELAYS
The Phoenix connector labeled RELAYS provides relay contacts 1 to 8 to control up to eight door
locks. If required, other devices can be controlled via these relay contacts through system
configuration and the REPORT command. When used as a lock relay, the contact number must
be the same as the door to which it is assigned. For interface wiring details, see Section 4.5.
The relays can support both normally open (N/O) locks and normally closed (N/C) locks. The lock
type is specified through the DOOR command. A normally closed lock is defined by replying 'Y'
to the REVERSE LOCK prompt. The default setting is for normally open door locks.
Figure 2-4: Door Lock Circuitry Block Diagram
20 MA
This connector is used to provide an interface with a terminal or host which must be located in
excess of 25 feet; the terminal or host can be at a maximum distance of 2,000 feet (610 meters)
from the ACU. This port and the host RS-232 port cannot be used concurrently. For 20 mA
connector interface wiring details, see Section 4.10.
HOST
The host connector on the Alto 818 is an RS-232C serial data port used to connect the ACU to
local devices such as a host computer, a second terminal, a printer, or an external communications
device. The maximum cable length from the ACU to a host port device is 25 feet (7.6 m). The
data sent to the host port by the ACU is the same as the data sent to the terminal port unless
specified otherwise with the REPORT command. For interface wiring details, see Section 4.7.