diff --git a/skeletons/Makefile.am b/skeletons/Makefile.am
index df3d3da..9b5b700 100644
--- a/skeletons/Makefile.am
+++ b/skeletons/Makefile.am
@@ -63,6 +63,7 @@
 	ber_tlv_tag.c ber_tlv_tag.h			\
 	constr_CHOICE.c constr_CHOICE.h			\
 	constr_SEQUENCE.c constr_SEQUENCE.h		\
+	constr_SEQUENCE_oer.c constr_SEQUENCE_oer.h	\
 	constr_SEQUENCE_OF.c constr_SEQUENCE_OF.h	\
 	constr_SET.c constr_SET.h			\
 	constr_SET_OF.c constr_SET_OF.h			\
diff --git a/skeletons/constr_SEQUENCE.h b/skeletons/constr_SEQUENCE.h
index c2aeb66..f20381a 100644
--- a/skeletons/constr_SEQUENCE.h
+++ b/skeletons/constr_SEQUENCE.h
@@ -6,6 +6,7 @@
 #define	_CONSTR_SEQUENCE_H_
 
 #include <asn_application.h>
+#include <constr_SEQUENCE_oer.h>
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/skeletons/constr_SEQUENCE_oer.c b/skeletons/constr_SEQUENCE_oer.c
new file mode 100644
index 0000000..18fefdf
--- /dev/null
+++ b/skeletons/constr_SEQUENCE_oer.c
@@ -0,0 +1,374 @@
+/*
+ * Copyright (c) 2017 Lev Walkin <vlm@lionet.info>.
+ * All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#ifndef ASN_DISABLE_OER_SUPPORT
+
+#include <asn_internal.h>
+#include <constr_SEQUENCE.h>
+#include <errno.h>
+
+/*
+ * This macro "eats" the part of the buffer which is definitely "consumed",
+ * i.e. was correctly converted into local representation or rightfully skipped.
+ */
+#undef  ADVANCE
+#define ADVANCE(num_bytes)                   \
+    do {                                     \
+        size_t num = num_bytes;              \
+        ptr = ((const char *)ptr) + num;     \
+        size -= num;                         \
+        consumed_myself += num;              \
+    } while(0)
+
+/*
+ * Switch to the next phase of parsing.
+ */
+#undef  NEXT_PHASE
+#undef PHASE_OUT
+#define NEXT_PHASE(ctx) \
+    do {                \
+        ctx->phase++;   \
+        ctx->step = 0;  \
+    } while(0)
+
+/*
+ * Check whether we are inside the extensions group.
+ */
+#define IN_EXTENSION_GROUP(specs, memb_idx)     \
+        ( ((memb_idx) > (specs)->ext_after)     \
+        &&((memb_idx) < (specs)->ext_before))
+
+/*
+ * Return a standardized complex structure.
+ */
+#undef  RETURN
+#define RETURN(_code)   do {                    \
+                rval.code = _code;              \
+                rval.consumed = consumed_myself;\
+                return rval;                    \
+        } while(0)
+
+asn_dec_rval_t
+SEQUENCE_decode_oer(asn_codec_ctx_t *opt_codec_ctx, asn_TYPE_descriptor_t *td,
+                   asn_oer_constraints_t *constraints, void **struct_ptr,
+                   const void *ptr, size_t size) {
+    asn_SEQUENCE_specifics_t *specs = (asn_SEQUENCE_specifics_t *)td->specifics;
+    asn_dec_rval_t rval = {RC_OK, 0};
+    void *st = *struct_ptr; /* Target structure */
+    asn_struct_ctx_t *ctx; /* Decoder context */
+    size_t consumed_myself = 0; /* Consumed bytes from ptr. */
+
+
+    (void)opt_codec_ctx;
+    (void)specs;
+
+    /*
+     * Create the target structure if it is not present already.
+     */
+    if(st == 0) {
+        st = *struct_ptr = CALLOC(1, specs->struct_size);
+        if(st == 0) {
+            RETURN(RC_FAIL);
+        }
+    }
+
+    /*
+     * Restore parsing context.
+     */
+    ctx = (asn_struct_ctx_t *)((char *)st + specs->ctx_offset);
+    if(ctx->ptr == 0) {
+        ctx->ptr = CALLOC(1, sizeof(asn_per_data_t));
+        if(!ctx->ptr) {
+            RETURN(RC_FAIL);
+        }
+    }
+
+    /*
+     * Start to parse where left previously.
+     */
+    switch(ctx->phase) {
+    case 0: {
+        /*
+         * Fetch preamble.
+         */
+        asn_per_data_t *preamble = ctx->ptr;
+        int has_extensions = (specs->ext_before >= 0);
+        size_t preamble_bits = (has_extensions + specs->roms_count);
+        size_t preamble_bytes = (preamble_bits >> 3);
+        uint8_t *pbytes;
+
+        if(size < preamble_bytes) {
+            ASN__DECODE_STARVED;
+        }
+
+        pbytes = MALLOC(preamble_bytes + 1);
+        if(!pbytes) {
+            RETURN(RC_FAIL);
+        }
+        preamble->buffer = (const void *)pbytes;
+        memcpy(pbytes, ptr, preamble_bytes);
+        pbytes[preamble_bytes] = '\0';    /* Just in case */
+        preamble->nboff = has_extensions;
+        preamble->nbits = preamble_bits;
+        ADVANCE(preamble_bytes);
+    }
+        NEXT_PHASE(ctx);
+        /* FALL THROUGH */
+    case 1: {
+        /* Decode components of the extension root */
+        asn_per_data_t *preamble = ctx->ptr;
+        size_t edx;
+
+        for(edx = (ctx->step >> 1); edx < td->elements_count;
+            edx++, ctx->step = (ctx->step & ~1) + 2) {
+            asn_TYPE_member_t *elm = &td->elements[edx];
+            void **memb_ptr2;   /* Pointer to a pointer to a memmber */
+
+            if(ctx->step & 1) {
+                goto microphase2_decode_continues;
+            }
+
+
+            if(IN_EXTENSION_GROUP(specs, edx)) {
+                /* Ignore non-root components in PHASE 1 */
+                continue;
+            }
+
+            if(elm->optional) {
+                int32_t present = per_get_few_bits(preamble, 1);
+                if(present < 0) {
+                    RETURN(RC_FAIL);
+                } else if(present == 0) {
+                    if(elm->default_value) {
+                        if(elm->flags & ATF_POINTER) {
+                            /* Member is a pointer to another structure */
+                            memb_ptr2 =
+                                (void **)((char *)st + elm->memb_offset);
+                        } else {
+                            void *memb_ptr = (char *)st + elm->memb_offset;
+                            memb_ptr2 = &memb_ptr;
+                        }
+                        /* Fill-in DEFAULT */
+                        if(elm->default_value(1, memb_ptr2)) {
+                            RETURN(RC_FAIL);
+                        }
+                    }
+                    /* The member is not present. */
+                    continue;
+                }
+                /* Present OPTIONAL or DEFAULT component. */
+            }
+
+            /*
+             * MICROPHASE 2: Invoke the member-specific decoder.
+             */
+            ctx->step |= 1; /* Confirm entering next microphase */
+        microphase2_decode_continues:
+            if(elm->flags & ATF_POINTER) {
+                /* Member is a pointer to another structure */
+                memb_ptr2 = (void **)((char *)st + elm->memb_offset);
+            } else {
+                void *memb_ptr = (char *)st + elm->memb_offset;
+                memb_ptr2 = &memb_ptr;
+            }
+
+            rval = elm->type->oer_decoder(opt_codec_ctx, elm->type,
+                                          elm->oer_constraints, memb_ptr2, ptr,
+                                          size);
+            switch(rval.code) {
+            case RC_OK:
+                ADVANCE(rval.consumed);
+                break;
+            case RC_WMORE:
+                ADVANCE(rval.consumed);
+                RETURN(RC_WMORE);
+            case RC_FAIL:
+                RETURN(RC_FAIL);
+            }
+        } /* for(all root members) */
+
+    }
+        NEXT_PHASE(ctx);
+        /* FALL THROUGH */
+    case 2: {
+        /* Cleanup preamble. */
+        asn_per_data_t *preamble = ctx->ptr;
+        asn_per_data_t *extadds;
+        int has_extensions = (specs->ext_before >= 0);
+        int extensions_present =
+            has_extensions && (((const uint8_t *)preamble->buffer)[0] & 0x80);
+        uint8_t unused_bits;
+        size_t len = 0;
+        ssize_t len_len;
+        uint8_t *ebytes;
+
+        union {
+            const uint8_t *cptr;
+            uint8_t *uptr;
+        } unconst;
+        unconst.cptr = preamble->buffer;
+        FREEMEM(unconst.uptr);
+        preamble->buffer = 0;
+
+        if(!extensions_present) {
+            ctx->phase = 10;
+            RETURN(RC_OK);
+        }
+
+        /*
+         * X.696 (08/2015) #16.1 (c), #16.4
+         * Read in the extension addition presence bitmap.
+         */
+
+        len_len = oer_fetch_length(ptr, size, &len);
+        if(len_len > 0) {
+            ADVANCE(len_len);
+        } if(len_len < 0) {
+            RETURN(RC_FAIL);
+        } else {
+            RETURN(RC_WMORE);
+        }
+
+        if(len == 0) {
+            /* 16.4.1-2 */
+            RETURN(RC_FAIL);
+        } else if(len > size) {
+            RETURN(RC_WMORE);
+        }
+
+        /* Account for unused bits */
+        unused_bits = 0x7 & *(const uint8_t *)ptr;
+        ADVANCE(1);
+        len--;
+        if(unused_bits && len == 0) {
+            RETURN(RC_FAIL);
+        }
+
+        /* Get the extensions map */
+        ebytes = MALLOC(len + 1);
+        if(!ebytes) {
+            RETURN(RC_FAIL);
+        }
+        memcpy(ebytes, ptr, len);
+        ebytes[len] = '\0';
+
+        extadds = preamble;
+        memset(extadds, 0, sizeof(*extadds));
+        extadds->buffer = ebytes;
+        extadds->nboff = 0;
+        extadds->nbits = 8 * len - unused_bits;
+
+        ADVANCE(len);
+    }
+        NEXT_PHASE(ctx);
+        ctx->step = (specs->ext_after + 1);
+        /* Fall through */
+    case 3:
+        for(; ctx->step < specs->ext_before; ctx->step++) {
+            asn_per_data_t *extadds = ctx->ptr;
+            size_t edx = ctx->step;
+            asn_TYPE_member_t *elm = &td->elements[edx];
+            void **memb_ptr2;
+
+            if(elm->flags & ATF_POINTER) {
+                /* Member is a pointer to another structure */
+                memb_ptr2 = (void **)((char *)st + elm->memb_offset);
+            } else {
+                void *memb_ptr = (char *)st + elm->memb_offset;
+                memb_ptr2 = &memb_ptr;
+                assert(elm->flags & ATF_POINTER); /* Extensions are indirect */
+            }
+
+            switch(per_get_few_bits(extadds, 1)) {
+            case -1:
+                /*
+                 * Not every one of our extensions is known to the remote side.
+                 * Continue filling in their defaults though.
+                 */
+                /* Fall through */
+            case 0:
+                /* Fill-in DEFAULT */
+                if(elm->default_value && elm->default_value(1, memb_ptr2)) {
+                    RETURN(RC_FAIL);
+                }
+                continue;
+            case 1: {
+                /* Read OER open type */
+                ssize_t ot_size = oer_open_type_get(opt_codec_ctx, elm->type,
+                                                    elm->oer_constraints,
+                                                    memb_ptr2, ptr, size);
+                if(ot_size > 0) {
+                    ADVANCE(ot_size);
+                } else if(ot_size < 0) {
+                    RETURN(RC_FAIL);
+                } else {
+                    /* Roll back open type parsing */
+                    per_get_undo(extadds, 1);
+                    ASN_STRUCT_FREE(*elm->type, *memb_ptr2);
+                    *memb_ptr2 = NULL;
+                    RETURN(RC_WMORE);
+                }
+                break;
+            }
+            default:
+                RETURN(RC_FAIL);
+            }
+        }
+
+        NEXT_PHASE(ctx);
+        /* Fall through */
+    case 4:
+        /* Read in the rest of Open Types while ignoring them */
+        for(;;) {
+            asn_per_data_t *extadds = ctx->ptr;
+            switch(per_get_few_bits(extadds, 1)) {
+            case 0:
+                continue;
+            case 1: {
+                ssize_t slurped = oer_open_type_slurp(ptr, size);
+                if(slurped > 0) {
+                    ADVANCE(slurped);
+                } else if(slurped < 0) {
+                    RETURN(RC_FAIL);
+                } else {
+                    per_get_undo(extadds, 1);
+                    RETURN(RC_WMORE);
+                }
+                continue;
+            }
+            case -1:
+                /* No more Open Type encoded components */
+                break;
+            default:
+                RETURN(RC_FAIL);
+            }
+            break;
+        }
+    }
+
+    return rval;
+}
+
+/*
+ * Encode as Canonical OER.
+ */
+asn_enc_rval_t
+SEQUENCE_encode_oer(asn_TYPE_descriptor_t *td,
+                   asn_oer_constraints_t *constraints, void *sptr,
+                   asn_app_consume_bytes_f *cb, void *app_key) {
+    asn_enc_rval_t er;
+    const uint8_t *buf;
+    const uint8_t *end;
+    size_t useful_bytes;
+    size_t req_bytes = 0;
+    int encode_as_unsigned;
+    int sign = 0;
+
+    er.encoded = -1;
+
+    return er;
+}
+
+#endif  /* ASN_DISABLE_OER_SUPPORT */
diff --git a/skeletons/constr_SEQUENCE_oer.h b/skeletons/constr_SEQUENCE_oer.h
new file mode 100644
index 0000000..dce71be
--- /dev/null
+++ b/skeletons/constr_SEQUENCE_oer.h
@@ -0,0 +1,20 @@
+/*-
+ * Copyright (c) 2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#ifndef	CONSTR_SEQUENCE_OER_H
+#define	CONSTR_SEQUENCE_OER_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <asn_application.h>
+#include <asn_codecs.h>
+
+oer_type_decoder_f SEQUENCE_decode_oer;
+oer_type_encoder_f SEQUENCE_encode_oer;
+
+#ifdef __cplusplus
+}
+#endif
+#endif	/* CONSTR_SEQUENCE_OER_H */
diff --git a/skeletons/oer_decoder.h b/skeletons/oer_decoder.h
index c2dc560..33acb87 100644
--- a/skeletons/oer_decoder.h
+++ b/skeletons/oer_decoder.h
@@ -2,8 +2,8 @@
  * Copyright (c) 2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
  * Redistribution and modifications are permitted subject to BSD license.
  */
-#ifndef	_OER_DECODER_H_
-#define	_OER_DECODER_H_
+#ifndef	OER_DECODER_H
+#define	OER_DECODER_H
 
 #include <asn_application.h>
 #include <oer_support.h>
@@ -37,8 +37,30 @@
     const void *buf_ptr,
     size_t size);
 
+/*
+ * Swallow the Open Type (X.696 (08/2015), #30) into /dev/null.
+ * RETURN VALUES:
+ *       0:     More data expected than bufptr contains.
+ *      -1:     Fatal error deciphering length.
+ *      >0:     Number of bytes used from bufptr.
+ */
+ssize_t oer_open_type_slurp(const void *bufptr, size_t size);
+
+/*
+ * Read the Open Type (X.696 (08/2015), #30).
+ * RETURN VALUES:
+ *       0:     More data expected than bufptr contains.
+ *      -1:     Fatal error deciphering length.
+ *      >0:     Number of bytes used from bufptr.
+ */
+ssize_t oer_open_type_get(asn_codec_ctx_t *opt_codec_ctx,
+                          struct asn_TYPE_descriptor_s *td,
+                          asn_oer_constraints_t *constraints, void **struct_ptr,
+                          const void *bufptr, size_t size);
+
+
 #ifdef __cplusplus
 }
 #endif
 
-#endif	/* _OER_DECODER_H_ */
+#endif	/* OER_DECODER_H */
diff --git a/skeletons/oer_encoder.h b/skeletons/oer_encoder.h
index 08d0d4c..6d33f1c 100644
--- a/skeletons/oer_encoder.h
+++ b/skeletons/oer_encoder.h
@@ -2,8 +2,8 @@
  * Copyright (c) 2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
  * Redistribution and modifications are permitted subject to BSD license.
  */
-#ifndef	_OER_ENCODER_H_
-#define	_OER_ENCODER_H_
+#ifndef	OER_ENCODER_H
+#define	OER_ENCODER_H
 
 #include <asn_application.h>
 
@@ -48,4 +48,4 @@
 }
 #endif
 
-#endif	/* _OER_ENCODER_H_ */
+#endif	/* OER_ENCODER_H */
diff --git a/skeletons/oer_support.h b/skeletons/oer_support.h
index 727d7db..2a7fcb9 100644
--- a/skeletons/oer_support.h
+++ b/skeletons/oer_support.h
@@ -3,8 +3,8 @@
  * All rights reserved.
  * Redistribution and modifications are oermitted subject to BSD license.
  */
-#ifndef	_OER_SUPPORT_H_
-#define	_OER_SUPPORT_H_
+#ifndef	OER_SUPPORT_H
+#define	OER_SUPPORT_H
 
 #include <asn_system.h>		/* Platform-specific types */
 
@@ -30,7 +30,7 @@
 
 
 /*
- * Fetch the length determinant (X.696 08/2015, #8.6) into *len_r.
+ * Fetch the length determinant (X.696 (08/2015), #8.6) into *len_r.
  * RETURN VALUES:
  *       0:     More data expected than bufptr contains.
  *      -1:     Fatal error deciphering length.
@@ -49,4 +49,4 @@
 }
 #endif
 
-#endif	/* _OER_SUPPORT_H_ */
+#endif	/* OER_SUPPORT_H */