module for installation

The HLM-491 OEM recording module is designed for recording and playback of high quality mono audio
(bandwidth 30 Hz – 10 kHz, S/N ratio 80 dB).

More information
Prices and ordering
3300 CZK without VAT
HLM-491 : Audio memory


Audio memory HLM-491

The module is designed for recording and playback of high quality monophonic sound (bandwidth 30 Hz – 10 kHz, S/N ratio 80 dB). Recording is performed on a standard SD memory card; the length of recording is limited only by the capacity of the card (for the standard 1 GB card it is 5.5 hours, in the special version it is possible to record up to a week of continuous recording even in a “circular” version, where the oldest part of the recording is overwritten by a new recording). The SD card stores files in RAW or WAV format (depending on the module version) in the standard FAT file system, if necessary, the sounds on the card can be edited using common Windows audio editing programs or the cards can be copied or backed up using common procedures, for example in Explorer.

The recording module has one line input to connect a signal source, one line output for the NF amplifier and a simple parallel control interface that accepts TTL levels (four signals to select a total of 16 messages, signals to start recording, start reading and indicate module operation).

Alternatively, a version with serial bus or I2C line control can be ordered; using these interfaces, it is possible to use an almost unlimited number of records, the module’s internal real-time clock, volume control and other functions.

Technical parameters:

Supply voltage4 – 8 V DC
Power consumptionapprox. 110 mA
Number of channels1*
Recording quality16 bit, 24 kHz sampling*
Record compression (on request)G.711, ADPCM
Link level0.775 Vef
Communication interface (optional)I2C, up to 2x servers. port
Control interfaceTTL, 6x input, 1x output
Spacing s/smin. 70 dB, type. 86 dB
Dimensions76 x 50 x 10 mm
Temperature range0 – 75 °C *

* – if necessary, the module can be upgraded to multi-channel, higher resolution and higher sampling rates.

Order and prices

Delivery times are generally in the range of 3 to 4 weeks (please enquire). Quantity discounts for orders over 100 pcs by agreement.

The modules are manufactured exclusively to order with a delivery time of approx. 4 weeks.
Voice module HLM-491 incl. cards, FOR PRODUCTION, delivery 4 weeks
excl. VAT 3300  CZK
incl. VAT 3993  CZK
Optional accessories:
Power supply for detector and/or amplifier, DIN rail or socket (please specify in the note) within 10 days
excl. VAT 2000  CZK
incl. VAT 2420  CZK



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