Bosch Plena Message Manager


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The Plena message manager is a high performance, highly versatile stand-alone digital message player. Applications range from spot announcements in supermarkets and theme parks to warning and evacuation messages in emergency situations.


Up to 12 messages can be stored in the internal 64Mbit EEPROM, without the need for data retention battery backup. Each message can have any length within the total available capacity. A PC uploads messages and configurations via RS-232 to the unit, which can then operate without a PC. The standard WAV format is used for messages with sample rates of 8 kHz to 24 kHz with 16-bit word length (linear PCM). This gives up to 500 seconds of recording time with a CD-quality signal-to-noise ratio. The use of linear PCM instead of a compressed audio format, such as MP3, ADPCM and u-law/A-law, ensures high-quality playback of all types of audio signals, including sound effects and special tones, such as attention chimes.

The unit has 12 contact closure trigger inputs for announcements. Each can be configured for a sequence of up to four messages from those available. In this way messages can be used in combination with other messages, optimizing flexibility and storage  space usage. When used together with the six-zone LBB 1925/10 Plena System Pre-Amplifier, a zone selection can be configured for each trigger input. The message manager communicates this selection to the LBB 1925/10 via an RS-232 connection. Continuous activation of a trigger input causes the corresponding message sequence to repeat.


Inputs The trigger inputs have a serial priority, i.e., input 1 has priority over input 2, input 2 over input 3, etc. The high priority trigger inputs 1-6 are only accessible as contacts on the rear panel to prevent accidental use. The lower priority trigger inputs 7-12 are also available as trigger switches on the front panel.

Integrity and Dependability 

The LBB 1965/00 can also play emergency/evacuation messages, as it fulfills the IEC 60849 standard. The microcontroller continually checks the data integrity of the system, and a watchdog circuit, in turn, checks the microcontroller. The unit monitors the D/A converter with a pilot tone, and the high priority trigger inputs (one to six) for cable short circuits and breaks. A 24 V battery backup connection with automatic fail-safe provides continued operation if the mains power should fail. A 20 kHz pilot tone can be mixed with the output signal to supervise the link to the next amplifier. This also works for loudspeaker supervision in combination with 20 kHz detectors. Any failure causes a red LED fault indication, and activates a fault output contact.

Loop-through Facility

The LBB 1965/00 provides a loop-through facility with balanced XLR and unbalanced cinch inputs and outputs. This allows the unit to be inserted into an existing audio link. As long as no announcements are playing, the signal input is routed to the output. If an announcement begins, the input signal is interrupted and the announcement is routed to the output.


Messages and configuration settings are uploaded from a PC. After uploading, the trigger inputs 7-12 can be configured by using the front panel switches, without the need for a new upload or even a PC. Message content can be monitored using the available headphone jack.

Technical Specifications

Mains Power Supply
Voltage 230/115 VAC, 10%, 50/60 Hz
Inrush current  1.5 A at 230 VAC / 3 A at 115 VAC
Max power consumption 50 VA
Battery power supply
Voltage 24 VDC, +15% / -15%
Current max 1 A
Supported sample rates (fs)    24 / 22.05 / 16 / 12 / 11.025 / 8 kHz      
Frequency response
@ fs=24kHz
@ fs=22.05kHz
100 Hz to 11 kHz (+1 / -3 dB)
100 Hz to 10 kHz (+1 / -3 dB )
@ fs=16kHz 100 Hz to 7.3 kHz (+1 / -3 dB )
@ fs=12kHz 100 Hz to 5.5 kHz (+1 / -3 dB)
@ fs=11.025kHz 100 Hz to 5 kHz (+1 / -3 dB)
@ fs=8kHz  100 Hz to 3.6 kHz (+1 / -3 dB)
Distortion <0.1% at 1 kHz
S/N (flat at max volume) >80 dB
Supervision DAC  1 Hz pilot tone
Line input  1 x
Connector  3-pin XLR, balanced
Sensitivity  1 V
Impedance  20 kohm
CMRR >25 dB (50 Hz-to 20 kHz) 
Line input 1 x
Connector  Cinch, unbalanced
Sensitivity 1 V
Impedance  20 kohm 
Trigger input 6 x
Connector  Screw
Activation Contact closure
Supervision method  Cable loop resistance check 
Line output 1 x
Connector  3-pin XLR, balanced
Nominal level  1 V, adjustable 
Impedance <100 ohm
Line output 1 x
Connector Cinch, unbalanced 
Nominal level  1 V, adjustable
Impedance <100 ohm
Message active output  1 x 
Connector  Screw
Relay  100 V, 2 A (voltage free, SPDT)
Fault output  1 x
Connector Screw 
Relay 100 V, 2 A (voltage free, SPDT)
Interconnection 1 x 
Connector  9-pin D-sub (RS-232) 
PC protocol  115 kb/s, N, 8, 1, 0 (upload)
LBB 1925/10 protocol  19.2 kb/s, N, 8, 1, 0 (zone control)


Data formatWAV-file, 16-bit PCM, mono
Memory capacity 64 Mb EEPROM
Recording/playback time 500 s @ fs=8 kHz
167 s @ fs=24 kHz 
Number of messages12 (maximum) 
Data retention time>10 years


Dimensions (H x W x D)  56 x 430 x 270 mm
2.20 x 16.92 x 10.62 inch
(19" wide, 1U high, with feet)    
WeightApprox. 3 kg
Mounting Stand-alone, 19” rack
Color Charcoal 


Operating temperature-10 C to +55 C (14 F to +131 F)     
Storage and transport temperature  -40 C to +70 C (-40 F to +158 F) 
Relative humidity <95%