diff --git a/numass-core/src/main/java/inr/numass/data/api/MetaBlock.java b/numass-core/src/main/java/inr/numass/data/api/MetaBlock.java
new file mode 100644
index 00000000..1c809246
--- /dev/null
+++ b/numass-core/src/main/java/inr/numass/data/api/MetaBlock.java
@@ -0,0 +1,46 @@
+package inr.numass.data.api;
+
+import java.time.Duration;
+import java.time.Instant;
+import java.util.*;
+import java.util.stream.Stream;
+
+/**
+ * A block constructed from a set of other blocks. Internal blocks are not necessary subsequent. Blocks are automatically sorted.
+ * Created by darksnake on 16.07.2017.
+ */
+public class MetaBlock implements NumassBlock {
+    private SortedSet<NumassBlock> blocks = new TreeSet<>(Comparator.comparing(NumassBlock::getStartTime));
+
+    public MetaBlock(NumassBlock... blocks) {
+        this.blocks.addAll(Arrays.asList(blocks));
+    }
+
+    public MetaBlock(Collection<NumassBlock> blocks) {
+        this.blocks.addAll(blocks);
+    }
+
+    @Override
+    public Instant getStartTime() {
+        return blocks.first().getStartTime();
+    }
+
+    @Override
+    public Duration getLength() {
+        return Duration.ofNanos(blocks.stream().mapToLong(block -> block.getLength().toNanos()).sum());
+    }
+
+    @Override
+    public Stream<NumassEvent> getEvents() {
+        return blocks.stream()
+                .sorted(Comparator.comparing(NumassBlock::getStartTime))
+                .flatMap(NumassBlock::getEvents);
+    }
+
+    @Override
+    public Stream<NumassFrame> getFrames() {
+        return blocks.stream()
+                .sorted(Comparator.comparing(NumassBlock::getStartTime))
+                .flatMap(NumassBlock::getFrames);
+    }
+}
diff --git a/numass-core/src/main/java/inr/numass/data/api/NumassBlock.java b/numass-core/src/main/java/inr/numass/data/api/NumassBlock.java
new file mode 100644
index 00000000..eafc97d6
--- /dev/null
+++ b/numass-core/src/main/java/inr/numass/data/api/NumassBlock.java
@@ -0,0 +1,36 @@
+package inr.numass.data.api;
+
+import java.time.Duration;
+import java.time.Instant;
+import java.util.stream.Stream;
+
+/**
+ * A single continuous measurement block. The block can contain both isolated events and signal frames
+ * <p>
+ * Created by darksnake on 06-Jul-17.
+ */
+public interface NumassBlock {
+    /**
+     * The absolute start time of the block
+     * @return
+     */
+    Instant getStartTime();
+
+    /**
+     * The length of the block
+     * @return
+     */
+    Duration getLength();
+
+    /**
+     * Stream of isolated events. Could be empty
+     * @return
+     */
+    Stream<NumassEvent> getEvents();
+
+    /**
+     * Stream of frames. Could be empty
+     * @return
+     */
+    Stream<NumassFrame> getFrames();
+}
diff --git a/numass-core/src/main/java/inr/numass/data/api/NumassPoint.java b/numass-core/src/main/java/inr/numass/data/api/NumassPoint.java
new file mode 100644
index 00000000..c9129a00
--- /dev/null
+++ b/numass-core/src/main/java/inr/numass/data/api/NumassPoint.java
@@ -0,0 +1,94 @@
+package inr.numass.data.api;
+
+import hep.dataforge.meta.Metoid;
+import hep.dataforge.values.Value;
+
+import java.time.Duration;
+import java.time.Instant;
+import java.util.stream.Stream;
+
+/**
+ * Created by darksnake on 06-Jul-17.
+ */
+public interface NumassPoint extends Metoid, NumassBlock {
+
+    String START_TIME_KEY = "start";
+    String LENGTH_KEY = "length";
+    String HV_KEY = "voltage";
+    String INDEX_KEY = "index";
+
+
+    Stream<NumassBlock> getBlocks();
+
+    /**
+     * Get the voltage setting for the point
+     *
+     * @return
+     */
+    default double getVoltage() {
+        return getMeta().getDouble(HV_KEY, 0);
+    }
+
+    /**
+     * Get the index for this point in the set
+     * @return
+     */
+    default int getIndex() {
+        return getMeta().getInt(INDEX_KEY, -1);
+    }
+
+    /**
+     * Get the first block if it exists. Throw runtime exception otherwise.
+     *
+     * @return
+     */
+    default NumassBlock getFirstBlock() {
+        return getBlocks().findFirst().orElseThrow(() -> new RuntimeException("The point is empty"));
+    }
+
+    /**
+     * Get the starting time from meta or from first block
+     *
+     * @return
+     */
+    @Override
+    default Instant getStartTime() {
+        return getMeta().optValue(START_TIME_KEY).map(Value::timeValue).orElseGet(() -> getFirstBlock().getStartTime());
+    }
+
+    /**
+     * Get the length key of meta or calculate length as a sum of block lengths. The latter could be a bit slow
+     *
+     * @return
+     */
+    @Override
+    default Duration getLength() {
+        return Duration.ofNanos(
+                getMeta().optValue(LENGTH_KEY).map(Value::longValue)
+                        .orElseGet(() -> getBlocks().mapToLong(it -> it.getLength().toNanos()).sum())
+        );
+    }
+
+    /**
+     * Get all events it all blocks as a single sequence
+     * <p>
+     * Some performance analysis of different stream concatenation approaches is given here: https://www.techempower.com/blog/2016/10/19/efficient-multiple-stream-concatenation-in-java/
+     * </p>
+     *
+     * @return
+     */
+    @Override
+    default Stream<NumassEvent> getEvents() {
+        return getBlocks().flatMap(NumassBlock::getEvents);
+    }
+
+    /**
+     * Get all frames in all blocks as a single sequence
+     *
+     * @return
+     */
+    @Override
+    default Stream<NumassFrame> getFrames() {
+        return getBlocks().flatMap(NumassBlock::getFrames);
+    }
+}
diff --git a/numass-core/src/main/java/inr/numass/data/api/NumassSet.java b/numass-core/src/main/java/inr/numass/data/api/NumassSet.java
new file mode 100644
index 00000000..49771ec4
--- /dev/null
+++ b/numass-core/src/main/java/inr/numass/data/api/NumassSet.java
@@ -0,0 +1,101 @@
+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package inr.numass.data.api;
+
+import hep.dataforge.meta.Metoid;
+import hep.dataforge.names.Named;
+import hep.dataforge.providers.Provider;
+import hep.dataforge.providers.Provides;
+import hep.dataforge.providers.ProvidesNames;
+import hep.dataforge.tables.Table;
+import hep.dataforge.values.Value;
+import org.jetbrains.annotations.NotNull;
+
+import java.time.Instant;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Optional;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/**
+ * A single set of numass points previously called file.
+ *
+ * @author <a href="mailto:altavir@gmail.com">Alexander Nozik</a>
+ */
+public interface NumassSet extends Named, Metoid, Iterable<NumassPoint>, Provider {
+    String DESCRIPTION_KEY = "info";
+    String NUMASS_POINT_PROVIDER_KEY = "point";
+
+    Stream<NumassPoint> getPoints();
+
+//    default String getDescription() {
+//        return getMeta().getString(DESCRIPTION_KEY, "");
+//    }
+
+    @NotNull
+    @Override
+    default Iterator<NumassPoint> iterator() {
+        return getPoints().iterator();
+    }
+
+    /**
+     * Get the first point if it exists. Throw runtime exception otherwise.
+     *
+     * @return
+     */
+    default NumassPoint getFirstPoint() {
+        return getPoints().findFirst().orElseThrow(() -> new RuntimeException("The set is empty"));
+    }
+
+    /**
+     * Get the starting time from meta or from first point
+     *
+     * @return
+     */
+    default Instant getStartTime() {
+        return getMeta().optValue(NumassPoint.START_TIME_KEY).map(Value::timeValue).orElseGet(() -> getFirstPoint().getStartTime());
+    }
+
+    /**
+     * Find first point with given voltage
+     *
+     * @param voltage
+     * @return
+     */
+    default Optional<NumassPoint> optPoint(double voltage) {
+        return getPoints().filter(it -> it.getVoltage() == voltage).findFirst();
+    }
+
+    /**
+     * List all points with given voltage
+     *
+     * @param voltage
+     * @return
+     */
+    default List<NumassPoint> getPoints(double voltage) {
+        return getPoints().filter(it -> it.getVoltage() == voltage).collect(Collectors.toList());
+    }
+
+    @Provides(NUMASS_POINT_PROVIDER_KEY)
+    default Optional<NumassPoint> optPoint(String voltage) {
+        return optPoint(Double.parseDouble(voltage));
+    }
+
+    @Override
+    default String defaultTarget() {
+        return NUMASS_POINT_PROVIDER_KEY;
+    }
+
+    @ProvidesNames(NUMASS_POINT_PROVIDER_KEY)
+    default Stream<String> listPoints() {
+        return getPoints().map(it -> Double.toString(it.getVoltage()));
+    }
+
+    default Optional<Table> getHvData() {
+        return Optional.empty();
+    }
+}
diff --git a/numass-core/src/main/java/inr/numass/data/api/SignalProcessor.java b/numass-core/src/main/java/inr/numass/data/api/SignalProcessor.java
new file mode 100644
index 00000000..8f2d212c
--- /dev/null
+++ b/numass-core/src/main/java/inr/numass/data/api/SignalProcessor.java
@@ -0,0 +1,11 @@
+package inr.numass.data.api;
+
+import java.util.stream.Stream;
+
+/**
+ * An ancestor to numass frame analyzers
+ * Created by darksnake on 07.07.2017.
+ */
+public interface SignalProcessor {
+    Stream<NumassEvent> analyze(NumassFrame frame);
+}
diff --git a/numass-core/src/main/java/inr/numass/data/api/SimpleBlock.java b/numass-core/src/main/java/inr/numass/data/api/SimpleBlock.java
new file mode 100644
index 00000000..a38ec952
--- /dev/null
+++ b/numass-core/src/main/java/inr/numass/data/api/SimpleBlock.java
@@ -0,0 +1,43 @@
+package inr.numass.data.api;
+
+import java.io.Serializable;
+import java.time.Duration;
+import java.time.Instant;
+import java.util.List;
+import java.util.stream.Stream;
+
+/**
+ * A simple in-memory implementation of block of events. No frames are allowed
+ * Created by darksnake on 08.07.2017.
+ */
+public class SimpleBlock implements NumassBlock, Serializable {
+    private final Instant startTime;
+    private final Duration length;
+    private final List<NumassEvent> events;
+
+    public SimpleBlock(Instant startTime, Duration length, List<NumassEvent> events) {
+        this.startTime = startTime;
+        this.length = length;
+        this.events = events;
+    }
+
+    @Override
+    public Instant getStartTime() {
+        return startTime;
+    }
+
+    @Override
+    public Duration getLength() {
+        return length;
+    }
+
+    @Override
+    public Stream<NumassEvent> getEvents() {
+        return events.stream();
+    }
+
+    @Override
+    public Stream<NumassFrame> getFrames() {
+        return Stream.empty();
+    }
+}
diff --git a/numass-core/src/main/java/inr/numass/data/api/SimpleNumassPoint.java b/numass-core/src/main/java/inr/numass/data/api/SimpleNumassPoint.java
new file mode 100644
index 00000000..3a6b52ec
--- /dev/null
+++ b/numass-core/src/main/java/inr/numass/data/api/SimpleNumassPoint.java
@@ -0,0 +1,41 @@
+package inr.numass.data.api;
+
+import hep.dataforge.meta.Meta;
+import hep.dataforge.meta.MetaBuilder;
+import hep.dataforge.meta.MetaHolder;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.List;
+import java.util.stream.Stream;
+
+/**
+ * A simple static implementation of NumassPoint
+ * Created by darksnake on 08.07.2017.
+ */
+public class SimpleNumassPoint extends MetaHolder implements NumassPoint {
+    private final List<NumassBlock> blocks;
+
+    /**
+     * Input blocks must be sorted
+     * @param voltage
+     * @param blocks
+     */
+    public SimpleNumassPoint(double voltage, Collection<? extends NumassBlock> blocks) {
+        super(new MetaBuilder("point").setValue(HV_KEY, voltage));
+        this.blocks = new ArrayList<>(blocks);
+        this.blocks.sort(Comparator.comparing(NumassBlock::getStartTime));
+    }
+
+    public SimpleNumassPoint(Meta meta, Collection<? extends NumassBlock> blocks) {
+        super(meta);
+        this.blocks = new ArrayList<>(blocks);
+        this.blocks.sort(Comparator.comparing(NumassBlock::getStartTime));
+    }
+
+    @Override
+    public Stream<NumassBlock> getBlocks() {
+        return blocks.stream();
+    }
+}