Default @type

Let's say I have some temperature / humidity data

    {
      "temperature" : 22.1,
      "humidity" : 44
    }

I can mark this up semantically using JSON-LD as follows (note the JSON-LD
at the link is a little wonky right now in terms of naming):
    {
      "@type" : "https://iotdb.org/iotdb/models/firmata-dht11",
      "@context" : "https://iotdb.org/iotdb/models/firmata-dht11",
      "temperature" : 22.1,
      "humidity" : 44
    }

Great, this record now has a type and proper definitions for temperature
and humidity.

But let's say I want to leave the record alone and use HTTP Links headers
to annotate, as per [1]. Obviously I get the @context. But how do I get the
@type associated with the record?

[1] http://www.w3.org/TR/json-ld/#interpreting-json-as-json-ld

Regards,

D.