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T.38 Real-Time vs HTTPS

When you talk about the differences between T.38 and HTTPS you’re really discussing two different ways to secure a fax transmission.

If you read our What is T.38? page we mentioned that early difficulties with T.38 spawned non-compliant ‘work-around’ solutions.

And HTTPS was one such solution.

Direct vs Indirect

T.38 gives you a secure, direct connection between the sender and receiver that does not require the add-ons that HTTPS does.

HTTPS requires two additional components to send a fax:

  • HTTPS Server: Specialized server that manages the actual faxing process
  • HTTPS Client: Transfers the document to/from the HTTPS Server

The extra steps necessary to send an HTTPS act like middle-men putting extra hands on your documents which opens up the opportunity that your content could changed and compromised mid-transit.

Real-Time vs Delayed

One of the major benefits of T.38 faxing is its direct connection capability. There are no extra paths that your fax has to take like it would with HTTPS.

Unlike HTTPS, real-time faxing gives you page-by-page confirmation. If the transmission gets interrupted you know which pages made it through and which ones didn’t. You won’t have to start faxing from the beginning – you just pick up where you got cut off. This is especially convenient when your sending large documents.

Encryption vs Encryption

The ‘S’ in HTTPS stands for ‘secure.’

By its very nature HTTPS is a secure protocol for communication so, is it any better or worse than T.38?

HTTPS answered the need to send faxes securely from the fax server through the Internet at a time when customers were migrating telephony solutions from PSTN to IP and discovering that VoIP was not reliable for Internet fax.

Initially T.38 solutions did not offer encryption and had inherited VoIP’s reputation for poor Internet fax delivery success rates.

However, HTTPS faxes are temporarily stored at the provider level which may or may not be HIPAA or SOX compliant, if you’re a healthcare or legal organization.

Faxes sent over T.38 SIP trunks are not stored, making them HIPAA and SOX compliant. This eliminates the possibility of an intruder altering or compromising the privacy of the content.

The combination of no data image storage and encryption enables full HIPAA compliance making encrypted T.38 IP fax services more secure than traditional dedicated fax lines.

T.38 can be made even more secure by use of encryption and T38faxservices by babyTEL is the first service provider in the world to offer military grade, patented AES-256 encryption that exceeds federal regulations for HIPAA and SOX for secure fax communications.


HTTPS faxes can only be delivered on PSTN and cannot take advantage of clean IP routes.

PSTN lines may be switched by carries to IP and back along the route especially as IP networks become more prevalent. In time, HTTPS fax services will become less reliable.

Additionally the transport cost of HTTPS is more expensive because you’re dealing with more equipment and more licences for intermediate servers.

With HTTPS you don’t get to take advantage of lower costs associated with direct T.38 delivery paths.

Lastly, HTTPS is not standards based. Your HTTPS fax solution is locked into a specific vendor while the T.38 protocol is continually and automatically updated with new advancements in standards and technology.