The SMS4 is a four channel, stereo audio meter. Each stereo meter pair comprises two 18 segment LED level displays and a digital audio LOCK indicator. The SMS4 can be used to display the levels of any combination of four digital (AES/EBU) and/or analog audio signals simultaneously.

Connections to the SMS4 on the rear panel are via pluggable screw terminals for the stereo analog audio and 110 Ohm AES/EBU digital inputs. The unit is also equipped with BNC connectors to accommodate 75 Ohm digital signal inputs.

When the SMS4 detects an AES/EBU digital signal at any input, it will automatically enable the digital monitor circuitry for that input. In the event that a stereo analog and digital signal is inadvertently connected to the input of the same meter pair, the digital signal will override. The LOCK tally on the front panel will illuminate to indicate that a meter pair is switched to a digital input signal. The SMS4 is equipped with an integral power supply ... no "wall warts".The use of a high quality toroidal power transformer minimizes stray EMF interference.