c# - Read Control Characters GS RS -

i've read barcodes control characters gs (ascii = dec 29, <f8>), rs (ascii = 30, <f9>), ... first console application, these chars filtered - have no idea , why.

if scan barcode redhat-linux-console characters available:

ü=:<f9>06<f8>1tbus0000420<f8>p4474453146<f8>q15<f8>2k14006956<f8>v204930<f8>30s81.031.59.264<f8>3s5500201767<f8>13yy<f9>eot 

but within console, chars <f9> <f8> missing.

my c#-code:

using system; using system.collections.generic; using system.linq; using system.text; using system.threading.tasks;  namespace consoleapplication3 {     class program    {       static void main(string[] args)       {         string text = console.readline();         console.writeline(text);         console.readline();       }    } } 

how can read these chars?

working example, returns characters:

    static void main(string[] args)     {          consolekeyinfo cki;          console.writeline("press escape (esc) key quit: \n");                 {             cki = console.readkey();             console.write(" --- pressed ");             console.writeline(cki.key.tostring());         } while (cki.key != consolekey.escape);      }