[Portserver II] issues on serial connection toward external device using RealPort

Hi all,
I’m new to Digi equipments as today I unpacked our PortServer II 16 and started to study the manual.

I configured the Ethernet connection toward the Digi from a supervision PC, and then configured every port to

word = 8 bit
stop = N
parity =1 bit

set flow range=1-16 ixon=on ixoff=on

dev = rp

I also installed the realPort manager on the PC.

what I have is that the Digi seems to work fine: I can telnet to it via port 771 and see the debug characters; if I connect the RJ45 miniloopback jack (included in the package) to port xx and then telnet to it using port 20xx, I can see what I type. According to the manual this means that RealPorts are well configured.
In this case I have all 6 middle LEDs turned on: LI POL CS RX ERR OVF.

However, when I try now to connect from port xx of the Digi to my external equipment, using a straight ethernet 8-wire cable, it doesn’t seem to work.
The only lit LEDs are LI and OVF, which are by the way the same lit when the port xx is connected to nothing). The telnet session is a blank terminal (it doesn’t refuse the connection, though).

What am I missing?
Does the Digi require a special cabling?

Thanks for the help!

Hello Carlo,

Most likley, the cabling is not correct.
An ethernet cable is not pinned the same as an rs232 cable.
Both may have rj45 type connectors, but the pinouts are different.
Take a look at the cable guide to help decide which pinouts you need to follow. The guide is here:

Thank you for the answer!
Too bad, I naively thought you would need only straight cables no matter what the physical signal was (Ethernet/Serial/etc…).

I will study the document suggested by you and try to build a couple of cables. Thanks!

One more question, if I may.
The 9pole<->RJ45 cable included in the package of the PortServer, which I used to do the starting configuration, has 10pins on the RJ45 jack!!
Does this mean that all the RJ45 jack plugged into the Digi need to have 10pins active?

If so, it would be a problem because the external equipments I need to connect all have serial interfaces with RJ45 8pin.

Thanks for the help! :slight_smile:


You can use 8-pin Ethernet cabling with the PortServer, but please note that you will lose 2 of the signals in doing so (pins 1 and 10). If you need the DCD signal that is on pin 10 normally, we do have an option called “Altpin” that can be setup on the port to allow pins 2 and 10 to swap, allowing you to use the DCD signal instead of DSR.