MiniMac MMD-4 · Compact audio message repeater, 4 messages

Installation and power

Minimac is small enough to be put almost anywhere; its chassis mounts on a wall or a table, and an optional 1U adapter mounts it in a rack. It records up to 4 minutes of 100 Hz to 8 kHz audio (16 bit PCM, uncompressed, 16 kHz sample rate) into non-volatile FLASH memory, which keeps the messages through a power outage.

• Power: a two-terminal pluggable connector, terminal 1 for 12 VDC and terminal 2 for ground. The unit draws 1 A when driving a speaker, 250 mA on the line output.
• The power pack (model MINIMAC-PS) is optional and not included; the power LED shows that the unit is powered.

Connections

• LINE IN (RCA): mono line level input for recording, 10 kΩ, compatible with the unbalanced outputs of most tape decks, CD players and DAT players.
• MIC IN (1/8 inch mini jack): mono microphone input for recording, up to 1.5 kΩ, compatible with most consumer grade low impedance microphones. The line and microphone inputs cannot be used at the same time; disconnect the line input for the microphone to work.
• LINE OUT (+, −): mono line level output, 600 Ω, transformer isolated, +4 dBm maximum, for the unbalanced inputs of most audio equipment or an amplified speaker.
• SPKR OUT (+, −): bridged mono speaker output, 4 W into 8 Ω or 6 W into 4 Ω. Connect the speaker directly across the two terminals; referencing either terminal to ground causes incorrect operation and may damage the unit.
• PLAY RELAY (N.C., COMM., N.O.): dry form C contact, active while a message plays, rated 1 A at 24 VDC, non-inductive load.
• COMMON: common ground for the remote control inputs.
• REC SETUP: connect to common momentarily to enter record setup mode.
• START: connect to common to play or record a message; maintain it to repeat the message.
• STOP: connect to common to stop playback.
• SELECT: connect to common for 2 seconds to enter message select mode, then step through the selections with further closures.

Recording a message

Messages are recorded locally from a microphone or a line source such as a tape deck or CD player, with the Record, Select, Start and Stop pushbuttons on the side of the unit or the matching remote inputs.

• Press Record to enter record mode; the REC LED blinks.
• Press Select to choose the message location, 1 to 4, shown on the MSG LED.
• Press Start to begin recording; the REC LED stays on. Set the recording level with the input level potentiometer.
• Press Stop to end the recording, or to leave record mode.
• To erase a message, select it, press Start, then press and hold Stop for about 2 seconds.

Playback and message selection

A contact closure from a user supplied pushbutton, motion sensor or other control device on the Start input, or the Start pushbutton, plays the default message; holding it repeats the message. The PLAY LED lights during playback while the MSG LED blinks the number of the message playing. Stop ends playback.

• Standard mode: each trigger plays the same message, the default one.
• Sequencing mode: each trigger plays the next message; after the last one, play starts again from the first.
• To choose the default, press and hold Select for 2 seconds; the selection starts at message 1, and further presses step through messages 2, 3 and 4. Selection 5 sequences through all valid messages.
• Press Start (Play) or Stop to store the current selection as the default.

Adjustments and indicators

• OUT level potentiometer: playback level, continuous from off to +4 dBm.
• IN level potentiometer: recording level, for an input of up to +4 dBm.
• PLAY LED: lit while a message plays.
• MSG LED: blinks the selected message number during select, play or record; lit steadily in sequential play mode.
• REC LED: blinks in record mode, steady while recording.
• POWER LED: lit while the unit is powered.