Accessing Serial Port from within System Timer Thread on Digi Connect ME 9210

I am using Digi ESP for NET+OS (7.5.2) on the Digi Connect ME 9210 platform.
I created a NET+OS Project which includes the TCP/Serial Transfer service.
The TCP/Serial Comm thread can read/write the com port perfectly fine but I am trying to read/write the serial port from a timer function that runs within the System Timer Thread and it fails to write to the serial port using the identical call that was used within the TCP/Serial Comm thread. Is there a way to read/write the serial port from within a timer function?
(i.e. wake up every 2 seconds and write a cmd to the serial port and then read the response?)

interrupts are disabled while you are inside system timer thread to ensure nothing else interrupts it. you cannot do anything interrupt related from it. All you can do is fill up a buffer that can be sent to UART once you are out of system timer thread.

That makes perfect sense. Thanks LeonidM