How to build a cable for connect an external data/fax modem to the RB2011

Hardware MikroTik hardware general
1

Hello.
I have 2 devices, the RB2011 RouterBOARD (with RJ45 serial port) and the US Robotics Data/Fax modem(with DB-25 pin serial port) …
How can I create a cable for connecting the Data/Fax modem to the RouterBOARD ?!
I want to send an AT command to the Data/Fax modem and receive result from the modem.
I don’t have any problem with the modem in the RouterOS(installed on x86 hardware) …

Thanks.

2

I made a cable with the following specifications but did not work properly …
RJ-45 <------> DB-25
Pin 1 <------> Pin 4
Pin 2 <------> Pin 20
Pin 3 <------> Pin 2
Pin 4 <------> Pin 7
Pin 5 <------> Pin 7
Pin 6 <------> Pin 3
Pin 7 <------> Pin 6
Pin 8 <------> Pin 5