So the last thread on T38 made me want to start a thread on FAX over IP via an ATA or something like the Adtran TA900 series.
From our experience, to be most successful w/ FAX over IP of any sort we've found that if you: 1.) Set baud to lowest setting fax can handle 2.) Lower print quality settings if possible 3.) Make sure to force G711 4.) Disable ECM and VAD on fax/modem tone detection
And then cross your fingers fax's are successful and consistent. Anyone else have other experiences or suggestions? Kenny
Agreed. The key really is g.711 (usually u-law) and low (read no) latency/jitter unless you can fully interop T.38 across the network. Most fax machines will auto-negotiate to the lower speeds when needed, but low to middle end Brother machines may be a major exception as they often have a poor T.30 implementation. -Scott From: voiceops-bounces at voiceops.org [mailto:voiceops-bounces at voiceops.org] On Behalf Of Kenny Sallee Sent: Friday, August 28, 2009 12:06 PM To: voiceops at voiceops.org Subject: [VoiceOps] FAX over VOIP networks So the last thread on T38 made me want to start a thread on FAX over IP via an ATA or something like the Adtran TA900 series.
From our experience, to be most successful w/ FAX over IP of any sort we've found that if you:
1.) Set baud to lowest setting fax can handle 2.) Lower print quality settings if possible 3.) Make sure to force G711 4.) Disable ECM and VAD on fax/modem tone detection And then cross your fingers fax's are successful and consistent. Anyone else have other experiences or suggestions? Kenny
I've spent more time playing with fax over IP networks than I would care to remember. Here's what we ended up doing (in Australia anyway). Typically we use cheap little linksys PAP-2T ATA's and have found these to work perfectly. 1/ ensure there is as low a latency as possible and zero jitter. We run QoS on private tails so this isnt too hard. 2/ we dont run T38 but instead ensure that all codecs in use along the entire path are g711A (711A is the PSTN standard here) 3/ Ensure there is NO transcoding going on anywhere - even between 711u and 711a - this will break faxing if there is 4/ In the linksys PAP-2T the FXS port gain settings need changing from defaults - we've found -1.5db to work well This last bit has been very important, otherwise for us the Linksys was providing too 'loud' a signal to the fax machine and would break faxing after say a page or two max. Using these settings, we have customers who send long (15-20) page faxes regularly with no problems. Additionally so far we havent had to change any fax machine settings, presumably the fax machines are simply training down to a speed they are happy with but we haven't spent much time looking at what they do in this regard - faxing works and thats all we cared about. Brent On Sat, Aug 29, 2009 at 3:03 AM, Scott Berkman <scott at sberkman.net> wrote:
Agreed.
The key really is g.711 (usually u-law) and low (read no) latency/jitter unless you can fully interop T.38 across the network. Most fax machines will auto-negotiate to the lower speeds when needed, but low to middle end Brother machines may be a major exception as they often have a poor T.30 implementation.
-Scott
*From:* voiceops-bounces at voiceops.org [mailto: voiceops-bounces at voiceops.org] *On Behalf Of *Kenny Sallee *Sent:* Friday, August 28, 2009 12:06 PM *To:* voiceops at voiceops.org *Subject:* [VoiceOps] FAX over VOIP networks
So the last thread on T38 made me want to start a thread on FAX over IP via an ATA or something like the Adtran TA900 series.
From our experience, to be most successful w/ FAX over IP of any sort we've found that if you:
1.) Set baud to lowest setting fax can handle
2.) Lower print quality settings if possible
3.) Make sure to force G711
4.) Disable ECM and VAD on fax/modem tone detection
And then cross your fingers fax's are successful and consistent. Anyone else have other experiences or suggestions?
Kenny
_______________________________________________ VoiceOps mailing list VoiceOps at voiceops.org https://puck.nether.net/mailman/listinfo/voiceops
-- -- Brent Paddon Director | Over the Wire Pty Ltd brent.paddon at overthewire.com.au | www.overthewire.com.au Phone: 07 3847 9292 | Fax: 07 3847 9696 | Mobile: 0400 2400 54 | Direct: 07 3503 4807
Yes, tweaking the gain is a wonderful method when curing echo issues. Lee Brent Paddon wrote:
I've spent more time playing with fax over IP networks than I would care to remember. Here's what we ended up doing (in Australia anyway).
Typically we use cheap little linksys PAP-2T ATA's and have found these to work perfectly.
1/ ensure there is as low a latency as possible and zero jitter. We run QoS on private tails so this isnt too hard. 2/ we dont run T38 but instead ensure that all codecs in use along the entire path are g711A (711A is the PSTN standard here) 3/ Ensure there is NO transcoding going on anywhere - even between 711u and 711a - this will break faxing if there is 4/ In the linksys PAP-2T the FXS port gain settings need changing from defaults - we've found -1.5db to work well
This last bit has been very important, otherwise for us the Linksys was providing too 'loud' a signal to the fax machine and would break faxing after say a page or two max. Using these settings, we have customers who send long (15-20) page faxes regularly with no problems. Additionally so far we havent had to change any fax machine settings, presumably the fax machines are simply training down to a speed they are happy with but we haven't spent much time looking at what they do in this regard - faxing works and thats all we cared about.
Brent
On Sat, Aug 29, 2009 at 3:03 AM, Scott Berkman <scott at sberkman.net <mailto:scott at sberkman.net>> wrote:
Agreed.
The key really is g.711 (usually u-law) and low (read no) latency/jitter unless you can fully interop T.38 across the network. Most fax machines will auto-negotiate to the lower speeds when needed, but low to middle end Brother machines may be a major exception as they often have a poor T.30 implementation.
-Scott
*From:* voiceops-bounces at voiceops.org <mailto:voiceops-bounces at voiceops.org> [mailto:voiceops-bounces at voiceops.org <mailto:voiceops-bounces at voiceops.org>] *On Behalf Of *Kenny Sallee *Sent:* Friday, August 28, 2009 12:06 PM *To:* voiceops at voiceops.org <mailto:voiceops at voiceops.org> *Subject:* [VoiceOps] FAX over VOIP networks
So the last thread on T38 made me want to start a thread on FAX over IP via an ATA or something like the Adtran TA900 series.
From our experience, to be most successful w/ FAX over IP of any sort we've found that if you:
1.) Set baud to lowest setting fax can handle
2.) Lower print quality settings if possible
3.) Make sure to force G711
4.) Disable ECM and VAD on fax/modem tone detection
And then cross your fingers fax's are successful and consistent. Anyone else have other experiences or suggestions?
Kenny
_______________________________________________ VoiceOps mailing list VoiceOps at voiceops.org <mailto:VoiceOps at voiceops.org> https://puck.nether.net/mailman/listinfo/voiceops
-- -- Brent Paddon
Director | Over the Wire Pty Ltd brent.paddon at overthewire.com.au <mailto:brent.paddon at overthewire.com.au> | www.overthewire.com.au <http://www.overthewire.com.au> Phone: 07 3847 9292 | Fax: 07 3847 9696 | Mobile: 0400 2400 54 | Direct: 07 3503 4807 ------------------------------------------------------------------------
_______________________________________________ VoiceOps mailing list VoiceOps at voiceops.org https://puck.nether.net/mailman/listinfo/voiceops
We're on a large install of Adtran TA900s here, and we've had good successes with g711u with no T.38 option with low/no jitter, but are moving over to T.38. In the lab, at least, T.38 works great, once we divert our FoIP traffic to an Adtran end-point so that we can avoid our Cisco-Tekelec interoperability issues. -Owen Scott Berkman wrote:
Agreed.
The key really is g.711 (usually u-law) and low (read no) latency/jitter unless you can fully interop T.38 across the network. Most fax machines will auto-negotiate to the lower speeds when needed, but low to middle end Brother machines may be a major exception as they often have a poor T.30 implementation.
-Scott
*From:* voiceops-bounces at voiceops.org [mailto:voiceops-bounces at voiceops.org] *On Behalf Of *Kenny Sallee *Sent:* Friday, August 28, 2009 12:06 PM *To:* voiceops at voiceops.org *Subject:* [VoiceOps] FAX over VOIP networks
So the last thread on T38 made me want to start a thread on FAX over IP via an ATA or something like the Adtran TA900 series.
From our experience, to be most successful w/ FAX over IP of any sort we've found that if you:
1.) Set baud to lowest setting fax can handle
2.) Lower print quality settings if possible
3.) Make sure to force G711
4.) Disable ECM and VAD on fax/modem tone detection
And then cross your fingers fax's are successful and consistent. Anyone else have other experiences or suggestions?
Kenny
------------------------------------------------------------------------
_______________________________________________ VoiceOps mailing list VoiceOps at voiceops.org https://puck.nether.net/mailman/listinfo/voiceops
-- Owen Roth Network Engineer, CCNP Impulse Internet Services http://impulse.net/customer-support mailto:owen at impulse.net Tech Support: 805-456-5800 w: 805-884-6332
On Fri, Aug 28, 2009 at 12:55 PM, Owen Roth <owen at impulse.net> wrote:
We're on a large install of Adtran TA900s here, and we've had good successes with g711u with no T.38 option with low/no jitter, but are moving over to T.38. In the lab, at least, T.38 works great, once we divert our FoIP traffic to an Adtran end-point so that we can avoid our Cisco-Tekelec interoperability issues.
-Owen
The TA's have a limitation of I think 4 T38 calls at a time tho correct? Depending on 900 vs 900e series...
Gen1 supports a single T.38 and Gen2 supports 4 T.38. Anything past that falls back to G.711 On Aug 28, 2009, at 1:30 PM, Kenny Sallee wrote:
On Fri, Aug 28, 2009 at 12:55 PM, Owen Roth <owen at impulse.net> wrote: We're on a large install of Adtran TA900s here, and we've had good successes with g711u with no T.38 option with low/no jitter, but are moving over to T.38. In the lab, at least, T.38 works great, once we divert our FoIP traffic to an Adtran end-point so that we can avoid our Cisco-Tekelec interoperability issues.
-Owen
The TA's have a limitation of I think 4 T38 calls at a time tho correct? Depending on 900 vs 900e series... _______________________________________________ VoiceOps mailing list VoiceOps at voiceops.org https://puck.nether.net/mailman/listinfo/voiceops
For the Adtran TA900e, but sure you are running AOS A02.03 SC or above if you're going to introduce T.38 into the network. If an Adtran IAD receives a T.38 re-invite and T.38 is disabled on that IAD it will reject the Invite with a 400 Bad Request instead of a 488 Not Acceptable when running the older code revisions. On a separate note, what Cisco and Tekelec issues are you referring too? -- Jason Nesheim ----- Original Message ----- From: "Mark Holloway" <mh at markholloway.com> To: "Kenny Sallee" <kenny.sallee at gmail.com> Cc: voiceops at voiceops.org Sent: Friday, August 28, 2009 7:52:52 PM Subject: Re: [VoiceOps] FAX over VOIP networks Gen1 supports a single T.38 and Gen2 supports 4 T.38. Anything past that falls back to G.711 On Aug 28, 2009, at 1:30 PM, Kenny Sallee wrote: On Fri, Aug 28, 2009 at 12:55 PM, Owen Roth < owen at impulse.net > wrote: We're on a large install of Adtran TA900s here, and we've had good successes with g711u with no T.38 option with low/no jitter, but are moving over to T.38. In the lab, at least, T.38 works great, once we divert our FoIP traffic to an Adtran end-point so that we can avoid our Cisco-Tekelec interoperability issues. -Owen The TA's have a limitation of I think 4 T38 calls at a time tho correct? Depending on 900 vs 900e series... _______________________________________________ VoiceOps mailing list VoiceOps at voiceops.org https://puck.nether.net/mailman/listinfo/voiceops _______________________________________________ VoiceOps mailing list VoiceOps at voiceops.org https://puck.nether.net/mailman/listinfo/voiceops
participants (7)
-
brent＠overthewire.com.au -
jnesheim＠cytek.biz -
kenny.sallee＠gmail.com -
lriemer＠bestline.net -
mh＠markholloway.com -
owen＠impulse.net -
scott＠sberkman.net