CVU to DVMS Converter

Upload CVU, download DVMS — no installs required

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Format Transition

CVU recordings become far more usable as DVMS. The conversion unlocks compact speech storage that CVU cannot provide.

Confidential Handling

All uploaded files are handled securely — CVU inputs are removed after processing, and DVMS outputs expire within 24 hours.

No Expertise Needed

The entire CVU to DVMS process is designed for simplicity. Drag your audio in, pick the format, and grab the output.

How to convert CVU to DVMS

1

Select files from Computer, Google Drive, Dropbox, URL or by dragging it on the page.

2

Choose dvms or any other format you need as a result (more than 200 formats supported)

3

Let the file convert and you can download your dvms file right afterwards

About formats

CVU is an unsigned variant of the CVS telephony audio format, differing in how delta-encoded values are represented in the binary stream. While CVS stores slope delta values as signed quantities, CVU treats them as unsigned, shifting the numerical interpretation of each sample. Both share the underlying CVSD modulation technique — 1-bit adaptive delta coding where step size varies according to recent output bit patterns — operating at comparable rates, typically 16 kbps for narrowband voice at 8 kHz. The signed-versus-unsigned distinction matters at the decoder, where correct interpretation determines proper waveform reconstruction. CVU files appear in telephony and embedded communication contexts where hardware adopted the unsigned convention. A practical advantage is straightforward interfacing with systems using unsigned arithmetic natively, avoiding sign extension in decoders. Like its signed counterpart, CVU achieves extreme bandwidth efficiency, compressing voice into compact bitstreams for constrained links. SoX supports CVU, providing a reliable path for converting these niche telephony recordings into modern formats for analysis or archival.
Developer: CCITT / ITU-T
Initial release: 1970
DVMS (Dutch Voice Messaging System) is a telephony-grade audio encoding born from the Netherlands' early push toward digital voicemail infrastructure. Deployed through KPN (formerly PTT Telecom) in the mid-1980s, the format stores mono voice data at a narrow 8 kHz sample rate, prioritizing compact message size over sonic breadth. Audio is compressed with a proprietary variant of logarithmic companding similar to European A-law encoding, squeezing recordings to roughly 8 kbit/s while keeping speech intelligible. Each file carries a small header identifying sample rate, compression type, and message metadata, which made automated routing across early PBX and voicemail systems straightforward. Although DVMS never gained traction outside Dutch telecom circles, it influenced how European carriers designed later voice messaging protocols. Tools like SoX and several legacy telephony libraries still read and write DVMS files, allowing archival playback of decades-old messages. Among its practical advantages: extremely small file sizes (a one-minute message occupies roughly 60 KB), reliable speech clarity despite aggressive compression, and a simple container layout that is easy to parse programmatically.
Developer: Dutch PTT Telecom
Initial release: 1984

Frequently Asked Questions

What makes DVMS a better choice than CVU?

CVU suffers from raw delta-modulated audio unreadable by standard software. DVMS offers telephony system integration.

What can I use to play DVMS?

You can open DVMS with SoX and German telephony voice mail systems.

Is there quality loss from CVU to DVMS?

The source CVU audio has inherently low fidelity. DVMS conversion preserves what is there while adding broad compatibility.

Can I do this conversion from my phone?

Yes. The online converter is platform-independent — use it from any computer, tablet, or smartphone with a web browser.

Are there limits on CVU to DVMS conversion?

Standard conversions work without restrictions for typical use. Premium plans provide additional speed and capacity for large workloads.

Is registration needed for this conversion?

No account is needed for standard conversions. Simply upload your CVU recording, choose DVMS, and download the result.