FaxTap for SIP, Release 2.0 on the Way
There are two versions of FaxTap for SIP: one for the end user that just wants to solve an FoIP problem, and one for the lawful-intercept (LI) OEM. Fax Tap for SIP 2.0, slated for release in late June, includes added features for both types of users.
FaxTap is an FoIP analysis tool that picks up where Wireshark leaves off. Wireshark will display the envelope of the PCM data, give you a SIP ladder, and, if it’s a T.38 call, give you something of a T.30 ladder. But it doesn’t render the image nor does it give you the T.30 ladder for a G.711 call. FaxTap does all of this and much more, including full support for T.38 version 3 with V.34 support. Version 2.0 will be easier to use and remove a hole in the LI OEM version that today the bad guys can sneak through.
For the end user we are adding a GUI to do something about the number of command-line arguments that must be passed in. This means that front-line tech support, in addition to the motivated equipment OEM, can easily take advantage of FaxTap for SIP, a product that is removing the mystery from FoIP call analysis.
As for the LI OEM, we are adding support for NSS/NSF (Non-Standard Facilities and Non-Standard Services). This is a tough nut to crack since NSF and NSS give the two communicating terminals the ability to step outside the T.30 protocol, which governs how standard fax terminals communicate. If the caller recognizes the answering machine’s ID and NSF and wants to utilize a proprietary facility, it may reply with an NSS, at which point FaxTap is in the dark, and must resort to guessing about what is going on.
The biggest guess is what modem is being used. If the two terminals are using a standard fax modem, FaxTap can analyze the frequency components of the data and hope that it gets a match to the signature of a standard fax modem. It will then attempt to decode the image data and then present the data to FaxTap’s image-conversion facility. If the image can be decoded … great. Otherwise FaxTap outputs the decoded binary file.
The same process is used to track multiple transitions from voice to fax to voice, etc, which the T.30 standard also supports.
If you are an LI OEM, why not add support for fax since FaxTap makes it easy and affordable? So, look into FaxTap for SIP 2.0. Interested? Email us or call 770-449-7775.