When you send the read request to TLServer it will start to send back the CR terminated strings back to the PLC and you need to use the INPUT$(1) command to read the string into internal variable and then convert them to numerical form (use the VAL or HEXVAL functions) and assign to DM.
One example you can follow is the "SynchronizeRTC.PC6" sample program in the folder:
c:\Trilogi\tl6\samples\FileService_Modem
The example reads the RTC data sent by TLServer. You can follow the same way to read file data sent by the TLServer when you send it the READ tag.