diff --git a/include/sxmp/sxmp.h b/include/sxmp/sxmp.h
index 948908e..44a2324 100644
--- a/include/sxmp/sxmp.h
+++ b/include/sxmp/sxmp.h
@@ -127,6 +127,7 @@ typedef struct __sxchannel_t {
   sxlink_t *link; /** < pointer to the underlying link */
   struct __link_rpc_list_type *rpc_list; /** < rpc functions list */
   int flags; /** < flags of the channel */
+  int type_id; /** < channel type id */
 } sxchnl_t;
 
 /* message flags */
diff --git a/lib/channel.c b/lib/channel.c
index 2c3e8f6..a6267e3 100644
--- a/lib/channel.c
+++ b/lib/channel.c
@@ -79,6 +79,7 @@ uint8_t _channel_open(sxlink_t *co, uint16_t *chid)
   chan->link = co;
   chan->rpc_list = rpclist;
   chan->flags = 0;
+  chan->type_id = typeid;
 
   pthread_mutex_lock(&co->idx_ch_lock);
   chidx = idx_allocate(&co->idx_ch);
@@ -172,6 +173,7 @@ sxchnl_t *sxchannel_open(sxlink_t *co, int type)
 
   /* ok all is fine */
   chan->cid = msg->mhead.reserve;
+  chan->type_id = type;
   ccid = chan->cid;
   pthread_mutex_lock(&co->idx_ch_lock);
   idx_reserve(&co->idx_ch, ccid);