# How to get a Linux machine serially connected to WR21 modem send data out to a dedicated remote server

**URL:** <https://forums.digi.com/t/how-to-get-a-linux-machine-serially-connected-to-wr21-modem-send-data-out-to-a-dedicated-remote-server/18498>\
**Category:** Digi TransPort WR (Series)\
**Tags:** linux-serial-digi-wr\
**Created:** [June 30, 2017, 3:41pm UTC](https://forums.digi.com/t/how-to-get-a-linux-machine-serially-connected-to-wr21-modem-send-data-out-to-a-dedicated-remote-server/18498 "2017-06-30T15:41:18Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![satishms](https://avatars.discourse-cdn.com/v4/letter/s/d26b3c/32.png) [@satishms](https://forums.digi.com/u/satishms)\
**Post date:** [June 30, 2017, 3:41pm UTC](https://forums.digi.com/t/how-to-get-a-linux-machine-serially-connected-to-wr21-modem-send-data-out-to-a-dedicated-remote-server/18498/1 "2017-06-30T15:41:18Z")

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Components:  
Terminal: Embedded Linux box  
Modem: DIGI Transport WR21  
ISP: Either AT & T or Verizon  
Remote Server: A Linux or Windows box

Connections:  
Terminal to Modem: Serial  
Modem - ISP: GSM

What is our goal?  
Terminal (Embedded Linux box) to be able to send data to the Remote Server every 10 minutes.

Questions:

1. What ( A ) settings and ( B ) commands can help me accomplish my goal?

Appreciate your help!

Thank you,  
Satish M S

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**Author:** ![James.Wilson](https://avatars.discourse-cdn.com/v4/letter/j/53a042/32.png) [@James.Wilson](https://forums.digi.com/u/James.Wilson)\
**Post date:** [July 3, 2017, 11:18am UTC](https://forums.digi.com/t/how-to-get-a-linux-machine-serially-connected-to-wr21-modem-send-data-out-to-a-dedicated-remote-server/18498/2 "2017-07-03T11:18:20Z")

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Hi

if you are trying to talk to a device over the internet then you should have a IP port number for the data seen on the serial interface to be sent to the other device.

within the wr21 you can use the multitx function found under Configuration - Network \> Interfaces \> Serial \> MultiTX Serial Ports \> MultiTX Serial Port 0

here you can assign the serial interface which in your case would be 0 and the internet IP and port of the other server.

if you need something else then this document might be helpful

[http://ftp1.digi.com/support/documentation/AN\_002\_TCPDIAL\_TCPPERM\_and\_reverse\_telnet.pdf](http://ftp1.digi.com/support/documentation/AN_002_TCPDIAL_TCPPERM_and_reverse_telnet.pdf)

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**Author:** ![satishms](https://avatars.discourse-cdn.com/v4/letter/s/d26b3c/32.png) [@satishms](https://forums.digi.com/u/satishms)\
**Post date:** [July 19, 2017, 10:14am UTC](https://forums.digi.com/t/how-to-get-a-linux-machine-serially-connected-to-wr21-modem-send-data-out-to-a-dedicated-remote-server/18498/3 "2017-07-19T10:14:50Z")

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Hi,

I also have another question:

What is the number to use with the ATD command for the modem to connect with the ISP? The ISP being Verizon or AT&T.

Thank you,