Port server TS 16

We have been using for a while Digi PortServer TS2/4 devices with our POS Systems and worked perfectly well.
Couple days ago we installed the first PortServer TS16 Rack on our network, but we cannot put it working with, apparently, the same configuration (real port) as TS2/4.
We are using a cable that only uses the RxD, TxD and GND (pins 5, 6 and 7) on digi side.

Can you provide some help?

We’re going to need more information than that. This would probably be a good thing to open a Support case about. The two products work essentially the same.