Frama franking machine ethernet issues

The University has been refurbishing the old Arup Building on the New Museums Site for the Cambridge Conservation Initiative and renamed it as the David Attenborough Building.

In the new building, we had problems with a Frama franking machine which wouldn't connect to the network:

• When the machine boots up, the ethernet link goes up and the device DHCPs to get an address but then disconnects.
• When trying a connection test or trying to frank something, the link never goes live (the interface doesn't go up from a physical/line level - not getting as far as IP) and it reports an error.

Oddly, if we disconnect the franking machine and connect something else to the wallport, that device works fine, even on 1Gbit/s connections.  If we connect the franking machine directly to a laptop (in my case, a Thunderbird adapter on a MacBook Air), it also works fine and can be pinged.  We've tried other wallports, cables and switchports without resolving the issue.

Some notes:

• The machine does, by design, disconnect from the network when it's not using it as a security measure (to minimise the chance of being hacked remotely).
• The connection is via a wall socket and probably 30-40m cable.
• The franking machine only has a 10Mbit/s half-duplex ethernet interface.
• The switch the machine was connecting to is a Cisco 2960X-48LPS-L (48-port PoE+ with 10G uplink).

Fixing the port speed to 100Mbit/s half-duplex did not resolve the issue.

I ended up solving it by putting an unmanaged Netgear 8-port 10/100 switch between it and the wallport and it works fine.

However, I also wondered if PoE was upsetting the controller in the franking machine so I disabled that and removed the Netgear.  That was working when I left, so that may have fixed up, but I'll have to check in and see how they're getting on, a couple of days later.