This selects whether a vendor-specific DHCP option's value is encoded as ASCII text or hex bytes, and switching the type resets cigDhcpServersVendorSpecificOptionValue to an empty string so the two fields don't end up in a mismatched, invalid state. Getting this right matters because vendor-specific sub-options under option 43 often carry binary configuration data (like an encoded IP or a proprietary structure) that must be entered as hex rather than plain text. For example, an admin configuring a binary call-server address sub-option would set this to hex(2) and then enter the value as 'c0:a8:01:0a' to represent 192.168.1.10 in raw bytes.