# "com/0" and "com/1" question

**URL:** <https://forums.digi.com/t/com-0-and-com-1-question/5312>\
**Category:** NET+OS\
**Created:** [February 23, 2007, 9:53am UTC](https://forums.digi.com/t/com-0-and-com-1-question/5312 "2007-02-23T09:53:22Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![marcm](https://avatars.discourse-cdn.com/v4/letter/m/439d5e/32.png) [@marcm](https://forums.digi.com/u/marcm)\
**Post date:** [February 23, 2007, 9:53am UTC](https://forums.digi.com/t/com-0-and-com-1-question/5312/1 "2007-02-23T09:53:22Z")

</div>

Hi,  
I am attempting to write a custom TCP -\> serial interpreter for an application and have managed to get the TCP part working well but I am having problems opening the COM ports on the Digi ME device we are using.

I am using the DigiConnect JTAG Devel board and Digi ESP devel environment and NET+OS 7.0.

I have managed to get com/0 to open by NULLing any references to it in appconf.h. This seems to be OK and will be used like that in the release but for debug I would like to use the com/1 port that is available on the devel board.

Is there any way to use com/1 ?? I ask because looking at the circuit diagrams for the devel board it looks as though the Serial Por2 maps through to the JTAG socket.

When I attempt to open com/1 in the code I keep getting an error -1 which means that it is already open by another resource.

If it cant be done then fair enough but I would like to get it working if it is possible.

Thanks  
Marc.

---

<div class="post-metadata">

**Author:** ![pjacobson](https://avatars.discourse-cdn.com/v4/letter/p/7c8e57/32.png) [@pjacobson](https://forums.digi.com/u/pjacobson)\
**Post date:** [May 12, 2007, 9:04pm UTC](https://forums.digi.com/t/com-0-and-com-1-question/5312/2 "2007-05-12T21:04:50Z")

</div>

There is support for /com/1, but only on the units that have the JTAG wing!!

You can route your dialog and standard out there, by using the Digi ESP properties, or by creating a new application and selecting /com/1.

---

<div class="post-metadata">

**Author:** ![charliek](https://avatars.discourse-cdn.com/v4/letter/c/94ad74/32.png) [@charliek](https://forums.digi.com/u/charliek)\
**Post date:** [May 14, 2007, 1:34pm UTC](https://forums.digi.com/t/com-0-and-com-1-question/5312/3 "2007-05-14T13:34:47Z")

</div>

Also, make sure to enable the second serial interface in bsp.h (set BSP\_SERIAL\_PORT\_2 to BSP\_SERIAL\_UART\_DRIVER). Please also note that when moving your application over to a JTAG’less module, you’ll need to remove this and the define in appconf.h or else you’ll cause a netosFatalError in netosStartup (i.e. before it hits applicationStart).