diff --git a/proto/mvlc.proto b/proto/mvlc.proto
new file mode 100644
index 0000000..312690f
--- /dev/null
+++ b/proto/mvlc.proto
@@ -0,0 +1,38 @@
+syntax = "proto3";
+
+import "google/rpc/status.proto";
+import "vme.proto";
+
+option cc_generic_services = true;
+
+package mesytec.mnode.mvlc;
+
+message ReadRegisterRequest
+{
+    uint32 address = 1;
+}
+
+message WriteRegisterRequest
+{
+    uint32 address = 1;
+    uint32 value = 2;
+}
+
+message WriteRegisterResponse
+{
+    optional google.rpc.Status status = 1;
+}
+
+message ReadRegisterResponse
+{
+    optional uint32 value = 1;
+    optional google.rpc.Status status = 2;
+}
+
+service MVLC
+{
+    rpc ReadRegister(ReadRegisterRequest) returns (ReadRegisterResponse);
+    rpc WriteRegister(WriteRegisterRequest) returns (WriteRegisterResponse);
+    rpc VMERead(mesytec.mnode.vme.ReadRequest) returns (mesytec.mnode.vme.ReadResponse);
+    rpc VMEWrite(mesytec.mnode.vme.WriteRequest) returns (mesytec.mnode.vme.WriteResponse);
+}
diff --git a/proto/service.proto b/proto/service.proto
index 2680a1e..4591a5c 100644
--- a/proto/service.proto
+++ b/proto/service.proto
@@ -1,19 +1,33 @@
 syntax = "proto3";
 
+import "google/protobuf/timestamp.proto";
+
+option cc_generic_services = true;
+
 package mesytec.mnode;
 
-message SearchRequest {
-  string query = 1;
-  int32 page_number = 2;
-  int32 results_per_page = 3;
+service PingService {
+  rpc Ping(mesytec.mnode.Ping) returns (Pong);
 }
 
 message Ping {
   int32 peer_id = 1;
   uint32 sequence_number = 2;
+  google.protobuf.Timestamp timestamp = 3;
 }
 
 message Pong {
   int32 peer_id = 1;
   uint32 sequence_number = 2;
 }
+service FooService {
+  rpc Foo(FooRequest) returns (FooResponse);
+}
+
+message FooRequest {
+  int32 foo_value = 1;
+}
+
+message FooResponse {
+  int32 bar_value = 1;
+}
diff --git a/proto/vme.proto b/proto/vme.proto
new file mode 100644
index 0000000..99e4dff
--- /dev/null
+++ b/proto/vme.proto
@@ -0,0 +1,78 @@
+syntax = "proto3";
+
+import "google/rpc/status.proto";
+
+option cc_generic_services = true;
+
+package mesytec.mnode.vme;
+
+enum DataWidth
+{
+    D16 = 0;
+    D32 = 1;
+}
+
+message AddressModifier
+{
+    uint32 value = 1;
+}
+
+enum EsstRate
+{
+    UNKNOWN = 0;
+    RATE_160MB = 1;
+    RATE_276MB = 2;
+    RATE_320MB = 3;
+}
+
+message ReadRequestOptions
+{
+    optional bool late_read = 1;
+    optional bool fifo_read = 2;
+    optional bool swapped_read = 3;
+    optional EsstRate esst_rate = 4;
+    optional uint32 max_transfers = 5;
+}
+
+message ReadRequest
+{
+    uint32 address = 1;
+    AddressModifier amod = 2;
+    DataWidth width = 3;
+    ReadRequestOptions options = 4;
+}
+
+message WriteRequest
+{
+    uint32 address = 1;
+    uint32 value = 2;
+    AddressModifier amod = 3;
+    DataWidth width = 4;
+}
+
+enum ResponseFlags
+{
+    NONE = 0;
+    TIMEOUT = 1;
+    BUS_ERROR = 2;
+    SYNTAX_ERROR = 3;
+}
+
+message ReadResponse
+{
+    repeated uint32 values = 1;
+    optional ResponseFlags flags = 2;
+    optional google.rpc.Status status = 3;
+}
+
+message WriteResponse
+{
+    optional ResponseFlags flags = 2;
+    optional google.rpc.Status status = 3;
+}
+
+service VmeAccess
+{
+    rpc Read(ReadRequest) returns (ReadResponse);
+    rpc Write(WriteRequest) returns (WriteResponse);
+}
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 2040594..26785bb 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -39,6 +39,7 @@ add_mnode_dev_executable(mesy_nng_sub_consumer)
 add_mnode_proto_dev_executable(mnode_proto_test1)
 add_mnode_proto_dev_executable(mnode_proto_ping_client)
 add_mnode_proto_dev_executable(mnode_proto_ping_server)
+add_mnode_proto_dev_executable(mnode_proto_rpc_ping_server)
 
 #add_subdirectory(qt)
 
diff --git a/src/mnode_proto_rpc_ping_server.cc b/src/mnode_proto_rpc_ping_server.cc
new file mode 100644
index 0000000..1b8d8d8
--- /dev/null
+++ b/src/mnode_proto_rpc_ping_server.cc
@@ -0,0 +1,53 @@
+#include <memory>
+
+#include <mesytec-mvlc/mesytec-mvlc.h>
+#include <mesytec-mvlc/util/signal_handling.h>
+#include "proto/service.pb.h"
+#include "proto/mvlc.pb.h"
+#include <mesytec-mnode/mnode_nng_async.h>
+#include "internal/argh.h"
+
+using namespace mesytec;
+using namespace std::literals;
+
+void print_service_descriptors(google::protobuf::Service &service)
+{
+    auto sd = service.GetDescriptor();
+    spdlog::info("service: full_name={}, index={}, method_count={}",
+        sd->full_name(), sd->index(), sd->method_count());
+
+    for (int i = 0; i < sd->method_count(); ++i)
+    {
+        auto md = sd->method(i);
+        auto it = md->input_type();
+        auto ot = md->output_type();
+        spdlog::info("  method: full_name={}, index={}, input_type={}, output_type={}",
+            md->full_name(), md->index(), it->full_name(), ot->full_name());
+    }
+}
+
+int main()
+{
+    namespace nng = mnode::nng;
+    spdlog::set_level(spdlog::level::debug);
+
+    mnode::PingService_Stub pingService(nullptr);
+    print_service_descriptors(pingService);
+
+    mnode::vme::VmeAccess_Stub vmeService(nullptr);
+    print_service_descriptors(vmeService);
+
+    mnode::mvlc::MVLC_Stub mvlcService(nullptr);
+    print_service_descriptors(mvlcService);
+
+    auto socket = nng::make_rep_socket();
+
+    if (int res = nng_listen(socket, "tcp://localhost:5555", nullptr, 0))
+    {
+        nng::mnode_nng_error("nng_listen", res);
+        return res;
+    }
+
+
+    return 0;
+}