Communications issues with PM870 meter in PSE v7.20

[Ramon_Delgado]

I have a customer that has three PM870 meters with ECC Cards that were manufactured in the last quarter of 2014 with the latest firmware revision and they are getting communications loss between these three meters and PSE version 7.20.  This communications loss happens every hour on the hour and lasts for approximately 2 minutes and then the communications returns.  These are just 3 of 30 PM8 meters that they have in there system but are the only ones that exhibiting this issue.  When I look at the meter onboard alarm log I do not see any power up/resets as a matter of fact the onboard alarm log is empty.  When I look at the ECC card Web page I see the Timeouts incrementing on the meter interface every time that the alarms comes into PSE so I do not suspect that it is a software issue.  There are devices connected to the RS485 port but none of these devices report any communications loss at all.  As a last ditch effort I even rolled back the firmware to one meter to rule out the firmware but issue still persists.  Has anyone else seen this before or have any thoughts oh how I can troubleshoot this issue.