SMA1-LPEA Interface Instructions
The SMA1-LPEA is a single channel, two way audio Interface box designed to be used with ETS speaker / microphones
(OR separated speakers and pre-amplified microphones) and Power Over Ethernet IP cameras. It contains a 2.5Watt
speaker power amplifier to drive a 70v speaker and an ETS microphone interface. The SMA1-LPEA also features installer
friendly termination of the cable runs and a standard RCA or 3.5mm audio output connectors. The SMA1-LPEA can be
connected to a “microphone” or “line” level input, and “line level” output of a POE IP camera.
SMA1-LPEA location and power
The SMA1-LPEA interface box is designed to be located any place along the IP camera CAT5 cable run. It must be
located in between the IP camera and the router or switcher as shown in figure 1.
NOTES-
1. The IP camera MUST be connected and operating before the SMA1-LPEA’s power indicator will illuminate.
2. The SMA1-LPEA will not work with standard IP cameras.
Microphone / Speaker Placement.
Locate the speaker
and
microphone near the area of interest in the space to be monitored. If a large area is to be
monitored, locate the speaker
and
microphone in the middle of the space if possible. Avoid mounting the speaker
and
microphone near air conditioning vents, light fixtures or electrical equipment. The speaker
and
microphone
should be
placed as close to the subject(s) as possible. 5 to 10 feet is ideal. The speaker
and
microphone are still useable in the
range of 15-25 feet in public address applications but is dependent on the level of background noise in the area.
Experimentation in the environment will determine what distances work best.
Microphone and Speaker Cable Runs
Recommended cable is: 2 each 22 gauge, stranded, two conductor shielded cables (one for the microphone and the
other for the speaker) between the SMA1 amplifier / interface and the speaker
and
microphone. Keep the cable run
distances under 1,000 feet (70v speakers only) and away from AC power sources, light fixtures and electrical equipment.
If you are using an 8 Ohm speaker, 100 feet is the maximum suggested distance with #22 cable
.
Make connections
as shown in the drawing below.
Adjusting the microphone “gain” and SMA1-LPEA “level” controls (audio output)
If the SMA1-LPEA will be plugged into a “microphone level” input of an IP camera, set the microphone gain slightly
clockwise (or 1/4 of a full turn) from full counter-clockwise. Then use the “level control” on the SMA1-LPEA to set a
volume that produces an acceptable audio level at the head end.
If the will SMA1-LPEA be used with a “line level” input, turn the gain control of the SM1 to 3/4 full clockwise and adjust the
level control on the SMA1-LPEA to produce the clearest audio level at the head end.
Adjusting the speaker volume
Adjust the audio input level for an acceptable volume level on the connected 70v speaker / microphone. If a decent
amount of volume cannot be achieved, place speaker gain range switch in the “High” position.
SMA1-LPEA Mode switch:
The SMA1-LPEA supports Both Modes A and B of IEEE802.3af POE. The SMA1-LPEA is
pre-configured for the most common use of the “end point” POE IEEE802.3af standard (mode A). If the power LED does
not illuminate in this position, try the mode B position (mid span).
