V-Tap ISDN BRI Manual EN v2.6 Dec 2018 © 2017-2018 Vidicode 23
3.3.10
SD Card settings
The SD card is used to store the recorded calls onto. Without an SD card
the recording of calls does not work. The V-Tap system stores the
recorded data as a WAV file per call in the G.711 A-Law format. This
takes 8000 bytes per second of storage space. The SD card must be
FAT32 formatted and is used as a big cyclic memory buffer, because the
oldest file is deleted automatically when the card is getting full.
The file names on the card are like “00000001.WAV”, “00000002.WAV”,
etc. No call data can be extracted from the name, only the date and time
of creation can be read from the directory list. The actual call data with
phone numbers is enclosed inside the WAV header of each file and can
be extracted by the Apresa or Call Recorder VoIP software on the PC.
The WAV files are optionally encrypted, in which case they cannot be
played directly by any media player (only noise is heard then).
In case of using a Tunnel server, the files are sent to the server as soon as
they are closed. So, data is not sent live to the sever, but only after the
call has ended or after a file has reached its maximum size.
In the case that no Tunnel server is used, the files are just stored on the
card until the user gets the card out. SD cards with recorded files on
them can be read and interpreted by the Call Recorder VoIP software on
the PC.
Files are not deleted from the card by the system. Files are written until
the card is full (error situation) or until the maximum number of files has
been reached, in which case the oldest files are overwritten.
Another function for the SD card is to define a fixed IP address for the V-
Tap unit; see
IP address
. Yet another function is to update the firmware.
Safely removal of the SD Card and Power Off.
. Press the button for 2 seconds (Amber & Blue LED OFF).
. Release the button (Amber LED flashing).
. Take out the SD card or the USB cable (power off).
NOTE:
The procedure above does not work when start/stop with the button is
set (see Button Mode). In that case, the SD card can just be taken out.
