HOW TO: Configure Modems With Digi PortServer and Digi One Products When Not Using the RealPort Driver

Native Modem Configuration

Modem Configuration requires familiarity with the specific modem being used. While the following procedure is sufficient for most cases, it may be necessary to take additional steps to properly configure your modem or to set your server or network for a specific application.


1) The Cable

Use a Standard Modem Cable. Pinouts are available from the Digi Support cabling links: 

Digi RJ45 to Modem DB25:

Digi RJ45 to Modem DB9:

Additional pinouts can be located on our support site:


2) Configure the port for the modem connectivity:

From your server prompt or telnet/SSH client, telnet or SSH to the Digi unit, login as root and issue the following commands.
     set port ra=## dev=prn 

Where ## represents the actual port number.

If using 8 wire (non-Digi) cabling where the Digi ports are RJ45, issue the following command: 

    set flow ra=## altpin=on 

Configure the top DTE baud rate for the modem: 

    set line ra=## baud=57600 


2) Connect to and configure the attached modem:


While at the Digi root prompt, connect directly to the port/modem using the following command:

     connect ##   

Where ## represents the port number, 16 for port 16. 

Enter AT to ensure the modem replies with OK.  If not, try turning on the modem echo  by entering ate1 if there is still no OK response from the modem, re-check the cable:


Save the modem connection rate you are currently connected at: 


Note: For US Robotics modems issue at&b1 this prior to at&w.

Disconnect from the connect session:
Type (ctrl)-[ . (control left-square bracket, period) to exit and close the connect session and return to the Digi prompt.


Issue the device setting command (choose from a, b or c) for the desired modem role:

a) Command for dial in and dial out:

     set port ra=## dev=mio 

b) Command for dial in only:

    set port ra=## dev=min

c) Command for dial out only:

    set port ra=## dev=mout

Implement hardware flow control (always recommended with modems):

     set flow ra=## cts=on rts=on ixon=off ixoff=off 

Last updated: May 20, 2019

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