1. Analyze the signaling exchange. The analysis shows that the peer side sends a BYE message before two pages of fax data is completely received during a fax process. As a result, sending the fax ends.
2. Capture packets and perform TDM trace. The analysis shows that the processing of the UA5000 is normal.
3. Record on the UMG side and make an analysis: The sending end (upper layer) sends the PRI-EOP command after finishing sending the second page of fax data, but the receiving end fax machine (lower layer) does not respond. The sending end resends the PRI-EOP command twice, but the receiving end fax machine still fails to respond. As a result, the problem occurs.
4. Test again after the ECM function is disabled on the UMG. The problem does not appear. Therefore, it is suspected that the fax machine on the PSTN side does not support the ECM function.
5. Enable the ECM function on the UMG and meanwhile replace the fax machine on the PSTN side. Test again. The test result is OK, which proves that the previous analysis is correct.
6. After the preceding analysis, it is proved that sending multiple pages of fax data fails because the fax machine on the PSTN side does not support the ECM function.Refer to the analysis report in the attachment.
2. UA5000 processing error.
3. UMG processing error.4. Cooperation error between the fax machines on the two sides.