From the Legend Pocket Reference, Release 7.0 enhancements:

"Release 7.0 software also supports the Caller ID capability of the 408 GS/LS-ID-MLX module. Although previously orderable, the Caller ID capability of this module could not beused until Release 7.0 software became available."

So, I don't think that your 408-GS/LS-ID modules will work with your R5 processor.

I _think_ the 800 GS/LS-ID will work, as DTMF says. Just set the LS-delay to "ON", no other settings to tweak it. It just waits for either the CID or the 2nd ring before sending the calls to the phones.