Fax machine cannot be used

Forums › New Zealand Mobile and Wireless › Fax machine cannot be used

1 | 2

chevrolux

4568 posts

Uber Geek

Trusted

#2484070 14-May-2020 22:00

Some of us have worked extensively with equipment that is older than ourselves (I.e. 30 years +).

The gist of what you want is, low speed data services like faxing and dialup dont work over VoIP because of the way audio is mucked around when its packaged up to be sent via IP. There is no where near the bandwidth of a straight-up analogue lines. Then there is jitter which screws with it even more.

There is a protocol called T.38. But for it to work properly, needs to be implemented end-to-end and support is just generally very varying across all the different voice networks.

RunningMan

6005 posts

Uber Geek

#2484171 15-May-2020 06:59

chevrolux: low speed data services like faxing and dialup dont work over VoIP because of the way audio is mucked around when its packaged up to be sent via IP.

This. In simplistic terms faxing was an analogue encoding of a digital signal, so the process went D->A->D from end to end. If you replace the analogue connection between the endpoints with VoIP with a lossy digital audio codec optimised for speech the process becomes D->A->D->A->D with information about the original analogue signal being lost in those 2 extra conversions. T.38 is way of removing the lossy voice codecs and getting the end to end signalling working, but it is often not fully implemented at both ends so will not work.

EDIT: Read this. Looks a bit dated, but so is faxing...

Bung

3372 posts

Uber Geek

Subscriber

#2484179 15-May-2020 07:47

cyril7: Hi Steve, your comment re pharmacies and doctors with the events of the past few weeks that has significantly changed and honestly I see and the bunch of pharmacists I know say, it's all changed.

Covit19 has buried fax in that industry well and good, anyone hanging on is in lala land

Cyril

I bet one thing that won't change is the ~$2 surcharge at each ending for dealing with a "faxed" prescription.

I can remember the unboxing of one of the first NZ fax machines in the POHQ data lab. About the size of a medium office photocopier.

sbiddle

29126 posts

Uber Geek

Moderator

Trusted

Biddle Corp

Lifetime subscriber

#2484444 15-May-2020 13:46

RunningMan:

chevrolux: low speed data services like faxing and dialup dont work over VoIP because of the way audio is mucked around when its packaged up to be sent via IP.

This. In simplistic terms faxing was an analogue encoding of a digital signal, so the process went D->A->D from end to end. If you replace the analogue connection between the endpoints with VoIP with a lossy digital audio codec optimised for speech the process becomes D->A->D->A->D with information about the original analogue signal being lost in those 2 extra conversions. T.38 is way of removing the lossy voice codecs and getting the end to end signalling working, but it is often not fully implemented at both ends so will not work.

EDIT: Read this. Looks a bit dated, but so is faxing...

Not quite.. Remember phone exchanges are digital and have been since NEAX's were installed from the late 70s. Your phone may be analogue, but it becomes a digital signal once it hits a NEAX, and uses alaw (or ulaw in the US) and SS7 for backhaul and interconnectivity to other networks.

daringpeter

32 posts

Geek

#2484619 15-May-2020 19:01

Oh well

There is always a problem in passing on third party information. AFAIK my friend was told that his fax machine ?analogue? wouldn't work although his phones- via a wifi network based on a modem- would... Who knows.

Handle9

4136 posts

Uber Geek

Trusted

Lifetime subscriber

#2484621 15-May-2020 19:06

daringpeter:

Oh well

There is always a problem in passing on third party information. AFAIK my friend was told that his fax machine ?analogue? wouldn't work although his phones- via a wifi network based on a modem- would... Who knows.

It won't work reliably. Other than that the why is pretty irrelevant. No one really cares anymore.

There is no business in providing fax equipment or services.

1 | 2