+SR_PRIV int dcttech_usbrelay_update_state(const struct sr_dev_inst *sdi);
+SR_PRIV int dcttech_usbrelay_switch_cg(const struct sr_dev_inst *sdi,
+ const struct sr_channel_group *cg, gboolean on);
+SR_PRIV int dcttech_usbrelay_query_cg(const struct sr_dev_inst *sdi,
+ const struct sr_channel_group *cg, gboolean *on);