Supply voltage/current: 10-30 Vdc, 50 ma (typ) Input data rate : 4800 baud (9800 selectable) Input drive voltage: 2-14V (active state) Input Impedance: 1K ohms (minimum) Talker output level: 4V differential (RS-422) Talker data rate: 4800 baud Output baud rate : 4800-38400 (selectable) Output formats: USB and RS-422 Indicator: Tri-color LED Size/weight: 3.75" x 3.0" x 1.0" / 4oz. Warranty- 2 year repair or replacement.

The NM42U multiplexer from NoLand Engineering combines up to four NMEA 0183 instruments into a common output. Two output formats, USB and RS-422, are provided. The output data rate is selectable at 4800 to 38400 baud. The multiplexer reads and stores the incoming data from each instrument. Whenever a complete message is received, the multiplexer automatically dumps it to the outputs while it continues reading the inputs. Therefore, complete messages are dumped as soon as they are received without any loss of input data. A "Talker" port is also included to allow a computer to request specific messages from instruments or to send data such as waypoints or steering commands.

Installation of the multiplexer is simple. The module may be mounted to any convenient surface with all connections made via a terminal strip. A USB connector is provided for PC connection if desired. The unit is fully automatic in that once power is applied, it immediately begins acquiring data without user interaction. Software drivers are provided to automatically configure a virtual COM port on a PC.

An LED shows operating status of the multiplexer. Green indicates an input is receiving valid data. Red indicates the talker port (TLK) is sending data. Yellow indicates an error has occured. Error messages are sent to the outputs to aid in fault isolation.