How to fetch a binary file from a remote embeded system using telnet?

I have a remote embedded system and it is telnet-able. How can I fetch a binary file from it using ruby? If it were a text file, I could have used:

  con = Net::Telnet::new("Host"=>ip,"Timeout"=>200)  #Host not host
  File.open("fetche开发者_如何学Pythond_file","w+") do |f|
        con.cmd("cat /ect/file")  {|data| f.write(data)}
  end

But this wouldn't work for binary file you won't get desirable data by cating it.

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establish your telnet connection then
send the command:

uuencode filename -

to the remote host, replacing filename with the filename

take the data you are sent and pass it to uudecode on your system

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If the device has uuencode installed, you could use that to 'wrap' the binary into printable characters. Other possibility is to run dd if=/etc/file 2>/dev/null to dump the data (however I am not completely certain this will word any better...)