Specifications

Alto 818 Installation and Operation
2-20 P/N 66109074001 Rev. D
2.5 SE 774-A MULTIPLE SWITCH
MONITOR (MSM)
The SE 774-A MSM, Figure 2-9, provides four monitoring point contact pairs. A monitor point may
be a door switch, request-to-exit switch, or other device. It is interfaced to the Alto 818 by coaxial
cable connected to a sensor port. With an MSM connected to each of the eight sensor ports, the
Alto 818 can monitor up to 32 points.
The SE 774-A MSM measures 6.5 inches (16.5 cm) by 5.7 inches (13.7 cm) by 2.75 inches (5.8
cm) deep.
Figure 2-9: SE 774-A Multiple Switch Monitor (MSM)
NOTE:
The Alto 818 can support both the earlier version of the MSM, the SE 774, or the present
version, the SE 774-A. However, all MSMs on a single ACU must be the same version. The
select switch (S1) on the MSM auto sensing PCA must be set to the appropriate position for
the model used (see Figure 2.3).