# Serial interface - Com 0
**URL:** https://forums.digi.com/t/serial-interface-com-0/5219
**Category:** NET+OS
**Created:** [February 11, 2003, 1:39pm UTC](https://forums.digi.com/t/serial-interface-com-0/5219 "2003-02-11T13:39:25Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Doddy](https://forums.digi.com/u/Doddy)
#### Post date: [February 11, 2003, 1:39pm UTC](https://forums.digi.com/t/serial-interface-com-0/5219/1 "2003-02-11T13:39:25Z")
Hi,I am trying to use the Serial API’s provided. I have writted a task that reads in data to the comm port then echoes it back when enter is pressed. This code works fine on Comm1 but if I change the comm port over to Comm0, the open command fails. I based my code from the nahttp example provided with the kit. Regards Mark
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### Author:  [@marcelobarrosalmeida](https://forums.digi.com/u/marcelobarrosalmeida)
#### Post date: [February 12, 2003, 2:29pm UTC](https://forums.digi.com/t/serial-interface-com-0/5219/2 "2003-02-12T14:29:33Z")
Very strange, my board works fine with both serial ports. Points to check: 1) bspconf.h BSP\_INCLUDE\_SERIAL\_DRIVER\_1 must be defined 2) devices.c where all devices are defined. 3) netos\_serl.c, function InstallSerlDevice() Debug this function to verify if your port is really “coming to live”. Bye