From the Net::Telnet doc:

The output record separator for print() and cmd() is set to "\n" by de
+fault, so that you don't have to append all your commands with a newl
+ine. To avoid printing a trailing "\n" use put() or set the output_re
+cord_separator to "".
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Which means whenever you use 'print' or 'cmd' it will send a newline, whether you wanted one or not.
Further:

In the input stream, each sequence of carriage return and line feed (i
+.e. "\015\012" or CR LF) is converted to "\n". In the output stream, 
+each occurrence of "\n" is converted to a sequence of CR LF. See binm
+ode() to change the behavior. TCP protocols typically use the ASCII s
+equence, carriage return and line feed to designate a newline.
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Eg: All newlines are sent as "\r\n", as that is how Telnet does newlines.

Maybe you should show some code where you tried changing the output_record_separator, or try using put() ?

C.