All of the OCTET STRING data is binary data. You are talking about presentation format. If you tell Perl to display it as hexadecimal it will be displayed as hexadecimal, if you want ASCII text it will be displayed as ASCII text. The translation functionality of Net::SNMP attempts examine the binary data and based on the content of try to provide the most appropriate presentation format. Without MIB information to guide the presentation format, this is what can be accomplished.