@Sadav Ansari wrote:The last  firmware that supported the SIP option on the ATA 186 was 3.2(1).The Table 14 on page 13 suggests that a firmware 3.2(4) for SIP exists:https://www.voipinfo.net/docs/cisco/cucm_b_compatibility-matrix-cucm-imp-10x.pdf

@Nithin Eluvathingal wrote:Did you succeed  download the file from the link shared ?Do you mean this link for the v3.2.1 SIP firmware ?:ata_03_02_01_sip_050616_a.zip 

@Nithin Eluvathingal wrote:Did you succeed  download the file from the link shared ?No. I did not see any download link.Which version was this link to?  Was it a SIP version ?

@Sadav Ansari wrote:The last  firmware that supported the SIP option on the ATA 186 was 3.2(1).Are you sure the v3.2(1) was the last one that supported SIP ?Googling for it suggests that it was v3.2(4).... I came to the Cisco community to find an aut...