One additional clue:
After connecting DLS5 to the TL260 via the LAN, an upload will successfully take place if I 'uncheck' the PC1832 upload request and attempt an upload of the TL260 data only. So this appears to be a handshake issue when the TL goes to the PC1832 to upload the data.
I have entered a number of different access codes in both the DLS5 software and at the keypad for  and  but still get the connection refused error.
Trying to upload the PC1832 config without the TL260 upload check fails the same way.
I attempted to get an email into DCS Tech support (firstname.lastname@example.org
) as their website state, but I just get a permanent email failure in response.