diff --git a/include/mcc/mcc_deserializer.h b/include/mcc/mcc_deserializer.h
index e556af4..afae187 100644
--- a/include/mcc/mcc_deserializer.h
+++ b/include/mcc/mcc_deserializer.h
@@ -126,7 +126,8 @@ protected:
             return MccDeserializerErrorCode::ERROR_OK;
         }
 
-        auto r_str = std::views::split(input, params.seq_delim);
+        // auto r_str = std::views::split(input, params.seq_delim);
+        auto r_str = std::views::split(input, params.elem_delim);
         VT val;
 
         auto it = r.begin();
diff --git a/include/mcc/mcc_pcm.h b/include/mcc/mcc_pcm.h
index 4838f21..5f75a99 100644
--- a/include/mcc/mcc_pcm.h
+++ b/include/mcc/mcc_pcm.h
@@ -106,6 +106,24 @@ class is_error_code_enum<mcc::impl::MccDefaultPCMErrorCode> : public true_type
 namespace mcc::impl
 {
 
+// The routine generates a sequence of length 'innerN'+2 elements.
+// Th e first element is 'start_border' and the last one is 'stop_border'
+// (i.e. it returns at least 2-elements std::vector)
+// 'innerN' is a number of inner elements
+static std::vector<double> mccGenerateBsplineKnots(double start_border, double stop_border, size_t innerN)
+{
+    std::vector<double> res(innerN + 2);
+    res.front() = start_border;
+    res.back() = stop_border;
+
+    if (innerN) {
+        const double step = (stop_border - start_border) / (innerN + 1);
+        std::ranges::for_each(std::views::iota(1, (int)innerN + 1),
+                              [&](auto const& i) { res[i] = start_border + i * step; });
+    }
+
+    return res;
+}
 
 // type of PCM corrections (algorithm used):
 //     PCM_TYPE_GEOMETRY - "classic" geometry-based correction coefficients
diff --git a/include/mcc/mcc_pzone.h b/include/mcc/mcc_pzone.h
index 4f0baa1..c34d956 100644
--- a/include/mcc/mcc_pzone.h
+++ b/include/mcc/mcc_pzone.h
@@ -13,12 +13,14 @@
 #include "mcc_concepts.h"
 #include "mcc_constants.h"
 #include "mcc_coordinate.h"
+#include "mcc_deserializer.h"
+#include "mcc_serializer.h"
 
 namespace mcc::impl
 {
 
 
-enum class MccPZoneErrorCode : int { ERROR_OK, ERROR_NULLPTR, ERROR_COORD_TRANSFROM, ERROR_PCM_COMP };
+enum class MccPZoneErrorCode : int { ERROR_OK, ERROR_NULLPTR, ERROR_COORD_TRANSFROM, ERROR_NO_PCM, ERROR_PCM_COMP };
 
 }  // namespace mcc::impl
 
@@ -56,6 +58,8 @@ struct MccPZoneCategory : public std::error_category {
                 return "input argument os nullptr";
             case MccPZoneErrorCode::ERROR_COORD_TRANSFROM:
                 return "coordinate transformation error";
+            case MccPZoneErrorCode::ERROR_NO_PCM:
+                return "PCM was not set";
             case MccPZoneErrorCode::ERROR_PCM_COMP:
                 return "PCM computation error";
             default:
@@ -89,6 +93,7 @@ public:
 
     MccAltLimitPZ(mcc_angle_c auto const& alt_limit, mcc_angle_c auto const& latitude)
         : _altLimit(MccAngle(alt_limit).normalize<MccAngle::NORM_KIND_90_90>()),
+          _latitude(MccAngle::normalizeAngle<MccAngle::NORM_KIND_90_90>(latitude)),
           _cosALim(cos(_altLimit)),
           _sinAlim(sin(_altLimit)),
           _cosLat(cos(latitude)),
@@ -106,6 +111,29 @@ public:
                                                   : KIND == MccAltLimitKind::MAX_ALT_LIMIT ? "MAXALT-ZONE"
                                                                                            : "ALTLIMIT-UNKNOWN";
 
+    template <mcc_angle_c T>
+    T altLimit() const
+        requires(!std::derived_from<T, MccAngle>)
+    {
+        return _altLimit;
+    }
+
+    MccAngle altLimit() const
+    {
+        return _altLimit;
+    }
+
+    template <mcc_angle_c T>
+    T latitude() const
+        requires(!std::derived_from<T, MccAngle>)
+    {
+        return _latitude;
+    }
+
+    MccAngle latitude() const
+    {
+        return _latitude;
+    }
 
     error_t inPZone(mcc_skypoint_c auto const& coords, bool* result)
     {
@@ -230,7 +258,7 @@ public:
 
 protected:
     double _altLimit, _cosALim, _sinAlim;
-    double _cosLat, _sinLat, _absLat, _latLim;
+    double _latitude, _cosLat, _sinLat, _absLat, _latLim;
 
     bool doesObjectReachZone(const double& dec_app)
     {
@@ -322,14 +350,83 @@ protected:
 };
 
 
+/*
+    to be serialized in format:
+        ALT-LIMIT<seq-delim>LATITUDE
+ */
+template <MccAltLimitKind KIND>
+struct MccSerializer<MccAltLimitPZ<KIND>> : MccSerializerBase {
+    constexpr static std::string_view serializerName{"MCC-ALTITUDE-PZONE-SERIALIZER"};
 
-/*  co-longitude axis (HA or AZ) limit switch prohibited zone */
+    template <mcc_serialization_params_c ParamsT = mcc_serialization_params_t>
+    error_t operator()(traits::mcc_output_char_range auto& output,
+                       MccAltLimitPZ<KIND> const& value,
+                       ParamsT const& params = mcc_serialization_params_t{})
+    {
+        MccSerializer<MccAngle> aser;
+
+        auto err = aser(output, value.altLimit(), params);
+        if (err) {
+            return mcc_deduced_err(err, MccSerializerErrorCode::ERROR_UNDERLYING_SERIALIZER);
+        }
+
+        std::format_to(std::back_inserter(output), "{}", params.seq_delim);
+
+        err = aser(output, value.latitude(), params);
+        if (err) {
+            return mcc_deduced_err(err, MccSerializerErrorCode::ERROR_UNDERLYING_SERIALIZER);
+        }
+
+        return MccSerializerErrorCode::ERROR_OK;
+    }
+};
+
+template <MccAltLimitKind KIND>
+struct MccDeserializer<MccAltLimitPZ<KIND>> : MccDeserializerBase {
+    static constexpr std::string_view deserializerName{"MCC-ALTITUDE-PZONE-DESERIALIZER"};
+
+    template <mcc_serialization_params_c ParamsT = mcc_serialization_params_t>
+    error_t operator()(traits::mcc_input_char_range auto const& input,
+                       MccAltLimitPZ<KIND>& value,
+                       ParamsT const& params = mcc_serialization_params_t{})
+    {
+        std::string_view s;
+        MccDeserializer<MccAngle> ades;
+
+        auto seq = std::views::split(params.seq_delim);
+        if (std::ranges::size(seq) < 2) {
+            s = utils::trimSpaces(seq, utils::TrimType::TRIM_BOTH);
+            MccAngle alt, lat;
+
+            auto err = ades(input, alt, params);
+            if (err) {
+                return MccDeserializerErrorCode::ERROR_UNDERLYING_DESERIALIZER;
+            }
+
+            err = ades(input, lat, params);
+            if (err) {
+                return MccDeserializerErrorCode::ERROR_UNDERLYING_DESERIALIZER;
+            }
+
+            value = MccAltLimitPZ<KIND>{alt, lat};
+        } else {
+            return MccDeserializerErrorCode::ERROR_INVALID_SERIALIZED_VALUE;
+        }
+
+        return MccDeserializerErrorCode::ERROR_OK;
+    }
+};
+
+
+
+/*  co-longitude axis (HA or AZ) and co-latitude (DEC, ZD) limit switch prohibited zone */
 
 template <MccCoordKind AXIS_KIND>
 class MccAxisLimitSwitchPZ : public mcc_pzone_interface_t<std::error_code>
 {
 public:
-    static_assert(AXIS_KIND == MccCoordKind::COORDS_KIND_AZ || AXIS_KIND == MccCoordKind::COORDS_KIND_HA_OBS,
+    static_assert(AXIS_KIND == MccCoordKind::COORDS_KIND_AZ || AXIS_KIND == MccCoordKind::COORDS_KIND_HA_OBS ||
+                      AXIS_KIND == MccCoordKind::COORDS_KIND_ZD || AXIS_KIND == MccCoordKind::COORDS_KIND_DEC_OBS,
                   "UNSUPPORTED AXIS TYPE!");
 
     typedef std::error_code error_t;
@@ -339,33 +436,84 @@ public:
     static constexpr MccProhibitedZonePolicy pzPolicy = MccProhibitedZonePolicy::PZ_POLICY_FLIP;
 
     //
-    // min_limit_val and max_limit_val are hardware encoder angles in radians!
+    // min_limit_val and max_limit_val are hardware encoder angles!
+    // pcm is nullptr or pointer to mcc_pcm_c
     //
-    MccAxisLimitSwitchPZ(mcc_angle_c auto const& min_limit_val,
-                         mcc_angle_c auto const& max_limit_val,
-                         mcc_pcm_c auto* pcm)
+    template <typename PCM_T>
+    MccAxisLimitSwitchPZ(mcc_angle_c auto const& min_limit_val, mcc_angle_c auto const& max_limit_val, PCM_T pcm)
+        requires(std::is_null_pointer_v<PCM_T> || mcc_pcm_c<std::remove_pointer_t<PCM_T>>)
         : _minLimit(min_limit_val), _maxLimit(max_limit_val)
     {
-        _correctForPCM = [pcm](MccSkyPoint const& skypt, MccGenXY* hw_coords) {
-            struct pcm_res_t {
-                double pcmX, pcmY;
+        if constexpr (std::is_null_pointer_v<PCM_T>) {
+            _correctForPCM = [](MccSkyPoint const&, MccGenXY*) -> error_t { return MccPZoneErrorCode::ERROR_NO_PCM; };
+        } else {
+            _correctForPCM = [pcm](MccSkyPoint const& skypt, MccGenXY* hw_coords) {
+                struct pcm_res_t {
+                    double pcmX, pcmY;
+                };
+
+                pcm_res_t res;
+
+                auto err = pcm->computeInversePCM(skypt, &res, hw_coords);
+
+                return mcc_deduced_err(err, MccPZoneErrorCode::ERROR_PCM_COMP);
             };
-
-            pcm_res_t res;
-
-            auto err = pcm->computeInversePCM(skypt, &res, hw_coords);
-
-            return mcc_deduced_err(err, MccPZoneErrorCode::ERROR_PCM_COMP);
-        };
+        }
     }
 
 
-    static constexpr std::string_view pzoneName = axisKind == MccCoordKind::COORDS_KIND_AZ ? "AZ_AXIS-LIMITSWITCH_ZONE"
-                                                  : axisKind == MccCoordKind::COORDS_KIND_HA_OBS
-                                                      ? "HA_AXIS-LIMITSWITCH_ZONE"
-                                                      : "UKNOWN";
+    static constexpr std::string_view pzoneName =
+        axisKind == MccCoordKind::COORDS_KIND_AZ        ? "AZ-AXIS-LIMITSWITCH-ZONE"
+        : axisKind == MccCoordKind::COORDS_KIND_HA_OBS  ? "HA-AXIS-LIMITSWITCH-ZONE"
+        : axisKind == MccCoordKind::COORDS_KIND_ZD      ? "ZD-AXIS-LIMITSWITCH-ZONE"
+        : axisKind == MccCoordKind::COORDS_KIND_DEC_OBS ? "DEC-AXIS-LIMITSWITCH-ZONE"
+                                                        : "UKNOWN";
 
 
+    template <mcc_angle_c T>
+    T minLimit() const
+        requires(!std::derived_from<T, MccAngle>)
+    {
+        return _minLimit;
+    }
+
+    MccAngle minLimit() const
+    {
+        return _minLimit;
+    }
+
+    template <mcc_angle_c T>
+    T maxLimit() const
+        requires(!std::derived_from<T, MccAngle>)
+    {
+        return _maxLimit;
+    }
+
+    MccAngle maxLimit() const
+    {
+        return _maxLimit;
+    }
+
+    template <typename PCM_T>
+    void setPCM(PCM_T pcm)
+        requires(std::is_null_pointer_v<PCM_T> || mcc_pcm_c<std::remove_pointer_t<PCM_T>>)
+    {
+        if constexpr (std::is_null_pointer_v<PCM_T>) {
+            _correctForPCM = [](MccSkyPoint const&, MccGenXY*) -> error_t { return MccPZoneErrorCode::ERROR_NO_PCM; };
+        } else {
+            _correctForPCM = [pcm](MccSkyPoint const& skypt, MccGenXY* hw_coords) {
+                struct pcm_res_t {
+                    double pcmX, pcmY;
+                };
+
+                pcm_res_t res;
+
+                auto err = pcm->computeInversePCM(skypt, &res, hw_coords);
+
+                return mcc_deduced_err(err, MccPZoneErrorCode::ERROR_PCM_COMP);
+            };
+        }
+    }
 
     error_t inPZone(mcc_skypoint_c auto const& coords, bool* result)
     {
@@ -439,6 +587,9 @@ protected:
                 time_ang = (_maxLimit - x) / MCC_SIDERAL_TO_UT1_RATIO;  // to UT1 scale
             }
         } else if constexpr (AXIS_KIND == MccCoordKind::COORDS_KIND_AZ) {
+            static_assert(false, "NOT IMPLEMENTED YET!!!");
+        } else {
+            static_assert(false, "NOT IMPLEMENTED YET!!!");
         }
 
         std::chrono::nanoseconds ns{
@@ -452,4 +603,74 @@ protected:
 };
 
 
+/*
+    to be serialized in format:
+        MIN_LIMIT<seq-delim>MAX_LIMIT
+ */
+template <MccCoordKind AXIS_KIND>
+struct MccSerializer<MccAxisLimitSwitchPZ<AXIS_KIND>> : MccSerializerBase {
+    constexpr static std::string_view serializerName{"MCC-AXIS-LIMIT-SWITCH-SERIALIZER"};
+
+    template <mcc_serialization_params_c ParamsT = mcc_serialization_params_t>
+    error_t operator()(traits::mcc_output_char_range auto& output,
+                       MccAxisLimitSwitchPZ<AXIS_KIND> const& value,
+                       ParamsT const& params = mcc_serialization_params_t{})
+    {
+        MccSerializer<MccAngle> aser;
+
+        auto err = aser(output, value.minLimit(), params);
+        if (err) {
+            return mcc_deduced_err(err, MccSerializerErrorCode::ERROR_UNDERLYING_SERIALIZER);
+        }
+
+        std::format_to(std::back_inserter(output), "{}", params.seq_delim);
+
+        err = aser(output, value.maxLimit(), params);
+        if (err) {
+            return mcc_deduced_err(err, MccSerializerErrorCode::ERROR_UNDERLYING_SERIALIZER);
+        }
+
+
+        return MccSerializerErrorCode::ERROR_OK;
+    }
+};
+
+
+template <MccCoordKind AXIS_KIND>
+struct MccDeserializer<MccAxisLimitSwitchPZ<AXIS_KIND>> : MccDeserializerBase {
+    static constexpr std::string_view deserializerName{"MCC-AXIS-LIMIT-SWITCH-DESERIALIZER"};
+
+    template <mcc_serialization_params_c ParamsT = mcc_serialization_params_t>
+    error_t operator()(traits::mcc_input_char_range auto const& input,
+                       MccAxisLimitSwitchPZ<AXIS_KIND>& value,
+                       ParamsT const& params = mcc_serialization_params_t{})
+    {
+        std::string_view s;
+        MccDeserializer<MccAngle> ades;
+
+        auto seq = std::views::split(params.seq_delim);
+        if (std::ranges::size(seq) < 2) {
+            s = utils::trimSpaces(seq, utils::TrimType::TRIM_BOTH);
+            MccAngle minLim, maxLim;
+
+            auto err = ades(input, minLim, params);
+            if (err) {
+                return MccDeserializerErrorCode::ERROR_UNDERLYING_DESERIALIZER;
+            }
+
+            err = ades(input, maxLim, params);
+            if (err) {
+                return MccDeserializerErrorCode::ERROR_UNDERLYING_DESERIALIZER;
+            }
+
+            // WARNING: the class below is created without the PCM-class pointer!!!
+            value = MccAxisLimitSwitchPZ<AXIS_KIND>{minLim, maxLim};
+        } else {
+            return MccDeserializerErrorCode::ERROR_INVALID_SERIALIZED_VALUE;
+        }
+
+        return MccDeserializerErrorCode::ERROR_OK;
+    }
+};
+
 }  // namespace mcc::impl