¶userdata

<call ...>
    <userdata method="read" card*="" model*="" label="" />
</call>

<response>
    <userdata status="status" time="">
        <b[] __type="" />
    </userdata>
</response>

__type here can be either bin or str

<call ...>
    <userdata method="write" card="" time="" model*="" label*="" >
        <b[] __type="str" />
    </userdata>
</call>

<response>
    <userdata status="status" />
</response>