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Right FAX - Cisco VG transmission error due to line quality issue

Level 3
Level 3


We are getting transmission error when we sent faxes to few numbers, mostly international numbers. The Right FAX vendor is claiming that the issue is caused due to line quality issues. Our setup is as below


RightFAX - H323 - Cisco VG - PRI - Service provider (Not touching the CUCM)


Which debug commands on the VG, can i use to verify this. Also is there any command in VG to increase the line quality for faxes in the VG. Please note that we have the same line working fine for the voice calls without any issues. Any help would be much appreciated.

3 Replies 3

Charles Hill
VIP Alumni
VIP Alumni

Ask rightfax if error correction mode is enabled.  


On physical fax machines using VoIP I have seen ecm cause poor line condition error on local calls, however ECM is suppose to resolve poor line conditions when making overseas faxes.


you can send a fax with ecm enabled and with it disabled to test.


hope this helps,

please rate helpful posts.


Right FAX just confirmed that ecm is enabled by default on Right FAX. I am attaching the VG config, any help would be much appreciated.

Please find the debug attached, in the debug I can see 

timestamp=1943793553 FR_BAD_CRC_LS_DATA 0x0 bytes 
timestamp=1943793553 fr-msg-tx  bad crc, 0 bytes

Any idea how the the bad CRC would hav been formed, when i checked under the controller there is no input/CRC errors.