Image MIME Reference
CNS-INF2
Comverse Network Systems INF2 Image
image/vnd.cns.inf2
VS
Group 3 Fax Image
image/g3fax
G3-Fax
A complete technical comparison of Comverse Network Systems INF2 Image and Group 3 Fax Image — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | CNS-INF2 | G3-Fax |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | ✕ No | ✕ No |
| EXIF Metadata | ✕ No | ✕ No |
| ICC Color Profile | ✕ No | ✕ No |
Comverse Network Systems INF2 Image
image/vnd.cns.inf2
Extension
.inf2
Container
Proprietary Comverse Container
Compression
Proprietary
Algorithm
Unknown (Proprietary Telecom Encoding)
Color Depth
Unknown
Developed by
Comverse Network Systems (Ann McLaughlin)
Released
1999
Magic Bytes
Unknown (Proprietary)
Group 3 Fax Image
image/g3fax
Extension
.g3
Container
Raw Bitstream
Compression
Lossless (CCITT Group 3)
Algorithm
CCITT Group 3 (Modified Huffman / READ)
Color Depth
1-bit (Monochrome)
Developed by
CCITT (now ITU-T) / IETF
Released
1980
Magic Bytes
None (Raw Bitstream)
Browser Support Comparison
| Browser | CNS-INF2 | G3-Fax |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
CNS-INF2
CNS-INF2 Strengths
- Historically allowed Comverse to standardize media transmission internally across their global telecom messaging platforms
Limitations
- Completely obsolete and non-functional outside of decommissioned telecom infrastructure
- Undocumented, closed-source binary structure
- Zero support in modern image processing libraries like ImageMagick, libvips, or FFmpeg
G3-Fax
G3-Fax Strengths
- Extremely efficient compression for 1-bit black-and-white text and line art
- Standardized via RFC 1494 for email and internet fax transmission
- Low bandwidth requirements
Limitations
- Raw format lacks metadata (such as image width and resolution), requiring out-of-band information to decode accurately
- Strictly limited to 1-bit monochrome imagery
- Zero native web browser support
When to choose which format
CNS-INF2
Use CNS-INF2 when…
- Legacy Telecom Infrastructure
- Historical Comverse Unified Messaging Systems
- Proprietary Server-to-Server Media Exchange
G3-Fax
Use G3-Fax when…
- Telefacsimile (Fax) Transmission
- Internet Fax (T.37)
- Document Archiving
- Telephony Systems