MacFi-mpe · Enhanced MP3 digital audio record/play system, with RS-232 control and audio file transfer

Overview

The MacFi-mpe is the enhanced MacFi-mp, an MP3 digital audio record/play system with up to 99 messages and 40 minutes of local recording (MacFi-mpe 40) in non-volatile flash memory (FLASH EPROM, 32 MB), without battery backup. Dynamic Message Length (DML) lets each message have its own duration. To the standard unit it adds RS-232 (serial) control of recording and playback, RS-232 download of MPEG 1 Layer 1, 2 or 3 (MP3) files, a synchronization relay, and front mounted controls for rack mount applications.

• Records MPEG 1 Layer 3 (MP3), variable bit rate; plays MPEG 1 Layer 1, 2 and 3 files transferred over RS-232.
• 50 Hz to 15 kHz, 80 dB dynamic range and signal to noise, THD below 0.5% at 1 kHz, typical.
• Wall or table mount, optional 1U rack adapter; 12 VDC, 1 A with the built-in power amplifier in use or 250 mA without.
• The optional ICM-25 Input Control Module adds 25 start inputs per module over RS-232.

Connections

• POWER: two terminal pluggable connector; +12 VDC at 1 A and ground.
• RS232: 3 position Euro style pluggable terminal; 1, receive; 2, transmit; 3, ground.
• CONNECTOR 1 (12 position pluggable terminal strip): 1, common for all inputs; 2 to 9, START 1 to START 8, connect to common to play messages 1 to 8; 10, STOP; 11 and 12, PLAY RELAY, Form A contact that closes while playing. Inputs take a mechanical contact or an open collector driver, 3 mA.
• CONNECTOR 2 (3 position terminal): 1, RECORD input, connect to common to enter record setup mode; 2 and 3, SYNC RELAY, Form A normally open contact (2 common, 3 closes to 2 when activated).
• Play and sync relays are dry contacts rated 1 A at 24 VDC, non-inductive load.
• AUDIO IN: LEVEL potentiometer (+4 dBm max.); MIC, mono 1/8″ mini jack, up to 1.5 kΩ, low impedance; LINE, mono RCA, 10 kΩ. Mic and line cannot be used at the same time.
• SYNC IN: line level RCA input, 10 kΩ, with an audio sensor that detects 100 ms tones, for automated sync track encoding.
• AUDIO OUT: LEVEL potentiometer (−∞ to +4 dBm); LINE, mono RCA, 600 Ω, transformer isolated; SPKR, bridged mono speaker output, 4 W into 8 Ω or 6 W into 4 Ω. Never reference either speaker terminal to ground.

Configuration switches

An 8 position DIP switch on the back sets the operation (up is OFF, down is ON); it is read only at power up. Settings marked as configurable over RS-232 take the value set by serial command.

• Switches 1 and 2, number of plays: OFF OFF, once; OFF ON, twice; ON OFF, three times; ON ON, four times, or 1 to 99 times as set with the PLS command.
• Switches 3 and 4, pause between plays: OFF OFF, 1 second; OFF ON, 5 seconds; ON OFF, 10 seconds; ON ON, 30 seconds, or 0 to 99 seconds or minutes as set with the PAS command.
• Switches 5 and 6, play method: OFF OFF, standard operation (a maintained closure repeats the sequence); OFF ON, play one sequence per closure, with a queue of up to 16 sequences; ON OFF, play while active; ON ON, re-trigger, a new activation interrupts the message playing.
• Switch 7, Play Next: ON lets START 8 (Connector 1, terminal 9) play the next valid message, starting with message 1 after power up; START 1 to 7 are then disabled.
• Switch 8, Memory Protect: OFF enables recording; ON locks the message memory.

Controls and indicators

The push buttons, LEDs and the two digit message number and status display are on the front panel.

• RECORD indicator: blinking in record setup mode; on while recording.
• SYNC indicator: flashes at each synchronization pulse, while sync is programmed automatically or manually and during playback.
• OVERDRIVE indicator: on when the input overdrives the system; reduce the input level.
• AUDIO SENSE indicator: on when an audio signal is present at an optimum level.
• RECORD SETUP, START/STOP and SELECT buttons: select, record and play messages as on the MacFi-mp; holding SELECT steps through the 99 messages by tens.
• MANUAL SYNC button: records a synchronization closure in real time; held while idle, it shows the current baud rate.
• Display: 1 to 99, message number; all segments cycling, no messages recorded; both decimal points blinking, location occupied; right decimal point solid, the delay, pause or repeat setting has been changed over RS-232; FC, bad block memory test; Hi or Lo, serial port at 115,200 or 9,600 baud.
• Holding START/STOP during power up restores the default DLY, PAS and PLY settings and the 9,600 baud rate.

Recording and playing from the panel and terminals

• Record locally: press RECORD SETUP (the RECORD LED blinks), choose the location with SELECT, set the level with the AUDIO SENSE and OVERDRIVE LEDs, press START/STOP and start the source, then press START/STOP to end. Record setup times out after 1 minute.
• Record remotely, messages 1 to 8: hold the RECORD input (Connector 2, terminal 1) to common, hold the message’s START input to common and start the source; release START to stop, then RECORD to leave record mode.
• Play locally: choose a recorded message with SELECT and press START/STOP; press it again to stop.
• Play remotely, messages 1 to 8: a momentary or maintained closure on a START input plays the message with the set repeat and pause; STOP ends it. The play relay is held for the whole sequence and drops for about 100 ms between sequences.
• Memory clear/test: hold RECORD SETUP while applying power until the RECORD indicator stays on; the display reads FC for up to 20 minutes. To erase one message, record less than 1 second into it.

RS-232 serial control

The serial port runs at 9,600 (default) or 115,200 baud, 8 data bits, 1 stop bit, no parity, no flow control, for a local user or controller over a short, reliable link; there is no error detection. Commands and replies are ASCII; the unit answers with the MFI> prompt, and every command ends with a carriage return ().

To toggle the baud rate, remove power, hold MANUAL SYNC and reapply power: the display shows Lo (9,600) or Hi (115,200).

• PLY message,repeat,pause: plays a message (1 to 99) a number of times (1 to 99) with a pause (+ seconds, − minutes); e.g. PLY6,10,+5. Messages in quotes, such as "1,2", play as one, up to eight. Several PLY commands are queued; with no message number the next available message plays.
• REC message,delay,time: records into a location (1 to 99) after a delay of 1 to 99 seconds, for a time of 1 to 99 seconds (+) or minutes (−); e.g. REC8,10,-4. The location is erased at once, the input is routed to the output for monitoring, and recording starts after a 1 second delay; it ends with STP, the time limit or the end of memory.
• STP: stops playback or recording and clears the message queue.
• DLD message: receives an MPEG 1 Layer 1, 2 or 3 file by 1K XMODEM, up to 128 kbps, into a location or the next empty one. ULD message: sends a message by XMODEM 1K.
• PLS 1 to 99: plays per trigger (default 1). PAS and DLY ±1 to 99: pause between repeats and delay before the first play, + seconds, − minutes (default 0). These three apply to starts from Connector 1.
• PRI message,E or D: enables or disables a message. DIR: lists the 99 locations, a number for a valid message, XX for an empty one, D before a disabled one. DEL message: deletes a message.
• BAS and TRE 0 or −12 to +12: bass and treble level in dB (default 0).
• STS 1 or 0: turns on or off the status messages sent to the port when a message starts or stops, for controlling other systems.
• CFG: restores the default settings (such as PAS and PLS) and 9,600 baud. SHP: erases all memory and resets every setting to factory default, ready again within about 10 seconds. RST: warm reset. SYS: diagnostic system information. LST: lists the commands. CFG, SHP, DEL and BBT ask for Y/N confirmation.

Synchronization

The sync relay can be programmed with up to 100 contact closures per message location, which it repeats at the same points of the message on every playback. Sync pulses must last at least 100 ms and be at least 100 ms apart.

• Automatic: while recording, each tone detected at SYNC IN stores a 250 ms sync pulse; on playback the sync relay closes at that point.
• Manual: while recording, each press of MANUAL SYNC stores a 250 ms sync pulse, played back the same way.
• The SYNC indicator flashes at each pulse during programming and playback.

Loading MP3 files from a PC

• Connect with a terminal program such as Windows HyperTerminal: choose the serial port (e.g. COM 1), 9600 bits per second (or 115200), 8 data bits, no parity, 1 stop bit, no flow control, and press Enter for the MFI> prompt.
• Send DLD with the message number; when “C” characters appear, send the file with the 1K Xmodem protocol.
• A voice quality MP3 file can be made with Windows Sound Recorder (MPEG Layer-3 format, e.g. 32 kbps, 24,000 Hz, mono, saved with the .MP3 extension); for full fidelity use commercial ripping or editing software.

Memory maintenance

• BBT, bad blocks test: flash memory may develop errors, heard as a slight click, generally not before 250,000 write/erase cycles. BBT maps out the bad blocks so that recording no longer uses them; it takes up to 20 minutes, erases all messages and restores the default configuration, and the unit does nothing else until the MFI> prompt returns.
• The same test runs from the panel by holding RECORD SETUP during power up (the display reads FC).
• Disabled messages may be overwritten with REC; DEL frees a single location, SHP erases the whole memory.