{"id":12,"date":"2021-09-16T05:43:29","date_gmt":"2021-09-16T05:43:29","guid":{"rendered":"http:\/\/6142d91ffa690c001662c35d"},"modified":"2021-11-09T12:23:56","modified_gmt":"2021-11-09T12:23:56","slug":"troubleshooting-with-faxes-in-grandstream-atas","status":"publish","type":"post","link":"https:\/\/jazchye.com\/index.php\/2021\/09\/16\/troubleshooting-with-faxes-in-grandstream-atas\/","title":{"rendered":"Troubleshooting with Faxes in Grandstream ATAs"},"content":{"rendered":"

In my previous post, I mentioned the pros and cons of T.38 fax. A major downside for T.38 faxing is that this protocol depends a lot on fax parameters. One particular set of parameters might work for others and might not work for you.<\/p>\n

Here I have listed down all the possible parameters which are worth trying if you are trying to configure T.38 on a Grandstream ATA<\/a> –<\/p>\n

1. Make sure the ATA device is on the latest firmware<\/p>\n

2. Make sure you are able to register the device and able to make phone calls<\/p>\n

3. Make sure the ITSP\/PBX supports T.38<\/p>\n

4. Ensure that Fax BAUD of the fax machine must be less than 14400, 9600, or less<\/p>\n

5. Configure “Use First Matching Vocoder in 200OK SDP” to “Yes”<\/p>\n

6. Configure “Preferred Vocoder choice 1” as “PCMU” or “PCMA” (depending on your region)<\/p>\n

7. Set “Fax Mode” to “T.38 (Auto Detect)”<\/p>\n

8. Set “Re-INVITE After Fax Tone Detected” to “Enabled”<\/p>\n

9. Set “Disable Line Echo Canceller (LEC)” to “Yes”<\/p>\n

10. Set “Jitter Buffer Type” to “Fixed”<\/p>\n

The majority of the customers will have their faxes working well and good to go after going through the checklist above. If it is not working still, perhaps you should raise a ticket to the Support team, and do not forget to provide a packet trace for them to analyze!<\/p>\n","protected":false},"excerpt":{"rendered":"

In my previous post, I mentioned the pros and cons of T.38 fax. A major downside for T.38 faxing is that this protocol depends a…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12,11,5],"tags":[],"class_list":["post-12","post","type-post","status-publish","format-standard","hentry","category-ata","category-foip","category-troubleshooting"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t