diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..0b5d77f
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+*~
+*.js
+node_modules
diff --git a/acs.coffee b/acs.coffee
index 4b66085..6821ccc 100644
--- a/acs.coffee
+++ b/acs.coffee
@@ -102,6 +102,12 @@ updateDevice = (currentRequest, actions, callback) ->
       updates["#{path}_writable"] = p[1] if p[1]?
       updates["#{path}_timestamp"] = now
 
+  if actions.customCommands?
+    for p in actions.customCommands
+      commandName = p[0]
+      updates["_customCommands.#{commandName}._value"] = p[1]
+      updates["_customCommands.#{commandName}._timestamp"] = now
+
   if Object.keys(updates).length > 0 or Object.keys(deletes).length > 0
     db.devicesCollection.update({'_id' : currentRequest.deviceId}, {'$set' : updates, '$unset' : deletes}, {}, (err, count) ->
       if (err)
@@ -174,6 +180,12 @@ runTask = (currentRequest, task, methodResponse) ->
             res = tr069.response(task._id, cwmpResponse)
             writeResponse(currentRequest, res)
           )
+        when tasks.STATUS_SAVE
+          db.saveTask(task, (err) ->
+            throw new Error(err) if err?
+            res = tr069.response(task._id, cwmpResponse)
+            writeResponse(currentRequest, res)
+          )
         else
           throw Error('Unknown task status')
     )
diff --git a/config.coffee b/config.coffee
index 5c9e453..4b2781c 100644
--- a/config.coffee
+++ b/config.coffee
@@ -49,3 +49,5 @@ exports.ALIASES = aliases
 
 # load authentication scripts
 exports.auth = require('./config/auth')
+
+exports.CUSTOM_COMMANDS = require('./config/custom_commands')
diff --git a/config/custom_commands-sample.json b/config/custom_commands-sample.json
new file mode 100644
index 0000000..b9200a0
--- /dev/null
+++ b/config/custom_commands-sample.json
@@ -0,0 +1,3 @@
+{
+  "seowon_frequencies" : "/^[0-9]+\\-SWU\\%2D9200\\-[0-9A-Z]+$/"
+}
diff --git a/config/custom_commands/seowon_frequencies.js b/config/custom_commands/seowon_frequencies.js
new file mode 100644
index 0000000..e39554c
--- /dev/null
+++ b/config/custom_commands/seowon_frequencies.js
@@ -0,0 +1,199 @@
+// Change frequency plans for Seowon devices.
+// Args format: 3532500 5000,3537500 5000,3542500 5000,3547500 5000,3552500 5000,3557500 5000,3505000 10000,3515000 10000,3525000 10000,3535000 10000,3545000 10000,3555000 10000
+var net = require('net');
+var PORT = 23;
+var USERNAME = 'admin';
+var PASSWORD = 'admin';
+
+var FREQUENCIES_REGEX = /\s*([\d]+)\.\s*Frequency\s*:\s*([\d]+)\s\(KHz\),\s*Bandwidth\s*:\s*([\d\.]+)\s*\(MHz\)/gm
+
+var telnetConnect = function(host, callback) {
+  var client = net.connect(PORT, host, function() {
+    // enter username
+    telnetExecute(USERNAME, client, "Password: ", function(err, response) {
+      if (err) return callback(err, client);
+      if (!timeout) return;
+      // enter password
+      telnetExecute(PASSWORD, client, "MT7109> ", function(err, response) {
+        if (!timeout) return;
+        clearTimeout(timeout);
+        return callback(err, client);
+      });
+    });
+  });
+  var timeout = setTimeout(function() {
+    timeout = null;
+    return callback('timeout', client);
+  }, 4000);
+}
+
+var telnetExecute = function(command, connection, prompt, callback) {
+  command += "\n";
+  var response = '';
+  var listener = function(chunk) {
+    response += chunk.toString();
+    if (response.slice(0 - prompt.length) == prompt) {
+      if (!timeout) return;
+      clearTimeout(timeout);
+      connection.removeListener('data', listener);
+      return callback(null, response.slice(command.length, 0 - prompt.length));
+    }
+  };
+
+  var end = function() {
+    if (!timeout) return;
+    clearTimeout(timeout);
+    connection.removeListener('end', end);
+    return callback(null, response.slice(command.length));
+  };
+
+  var timeout = setTimeout(function() {
+    timeout = null;
+    return callback('timeout', response);
+  }, 2000);
+
+  if (prompt)
+    connection.on('data', listener);
+  else
+    connection.on('end', end);
+
+  if (command)
+    connection.write(command);
+}
+
+var parseFrequencies = function(frequenciesString) {
+  var a = frequenciesString.split(',')
+  var l = [];
+  for (i in a) {
+    var sp = a[i].trim().split(' ');
+    var frequency = parseInt(sp[0]);
+    var bandwidth = parseFloat(sp[1]);
+    l.push([frequency, bandwidth]);
+  }
+  return l;
+}
+
+var findFrequency = function(haystack, needle) {
+  for (i in haystack) {
+    if (haystack[i][0] == needle[0] && haystack[i][1] == needle[1])
+      return i;
+  }
+  return -1;
+}
+
+var getDeviceIp = function(deviceId, callback) {
+  var db = require('../../db');
+  var URL = require('url');
+
+  db.devicesCollection.findOne({_id : deviceId}, {'InternetGatewayDevice.ManagementServer.ConnectionRequestURL._value' : 1}, function(err, device) {
+    var connectionRequestUrl = device.InternetGatewayDevice.ManagementServer.ConnectionRequestURL._value;
+    var url = URL.parse(connectionRequestUrl);
+    return callback(url.hostname);
+  });
+};
+
+exports.init = function(deviceId, args, callback) {
+  return exports.get(deviceId, args, callback);
+};
+
+exports.get = function(deviceId, args, callback) {
+  var currentFrequencies = [];
+
+  getDeviceIp(deviceId, function(ip) {
+    telnetConnect(ip, function(err, client) {
+      // enter privileged mode
+      telnetExecute("enable", client, "MT7109# ", function(err, response) {
+        if (err) return callback(err);
+        // show frequencies
+        telnetExecute("show wmx freq", client, "MT7109# ", function(err, response) {
+          if (err) return callback(err);
+          while (f = FREQUENCIES_REGEX.exec(response)) {
+            var frequency = parseInt(f[2]);
+            var bandwidth = Math.floor(parseFloat(f[3]) * 1000);
+            var freqStr = String(frequency) + ' ' + String(bandwidth);
+            currentFrequencies.push(freqStr);
+          }
+          // log out
+          telnetExecute("logout", client, null, function(err, response) {
+            return callback(err, currentFrequencies.join(','));
+          });
+        });
+      });
+    });
+  });
+};
+
+exports.set = function(deviceId, args, callback) {
+  var newFrequencies = parseFrequencies(args);
+  var addFrequencies = [];
+  var delFrequencies = [];
+
+  getDeviceIp(deviceId, function(ip) {
+    telnetConnect(ip, function(err, client) {
+      // enter privileged mode
+      telnetExecute("enable", client, "MT7109# ", function(err, response) {
+        if (err) return callback(err);
+        // show frequencies
+        telnetExecute("show wmx freq", client, "MT7109# ", function(err, response) {
+          if (err) return callback(err);
+          while (f = FREQUENCIES_REGEX.exec(response)) {
+            var index = parseInt(f[1]);
+            var frequency = parseInt(f[2]);
+            var bandwidth = Math.floor(parseFloat(f[3]));
+
+            var i = findFrequency(newFrequencies, [frequency, bandwidth * 1000]);
+            if (i == -1)
+              delFrequencies.push(index);
+            else
+              newFrequencies.splice(i, 1);
+          }
+          for (f in newFrequencies)
+            addFrequencies.push(newFrequencies[f]);
+
+          if (addFrequencies.length == 0 && delFrequencies.length == 0) {
+            // log out
+            telnetExecute("logout", client, null, function(err, response) {
+              return callback(err, args);
+            });
+            return;
+          }
+
+          telnetExecute("wimax", client, "MT7109 (WiMax)# ", function(err, response) {
+            if (err) return callback(err);
+            var add, del;
+            del = function() {
+              if (delFrequencies.length == 0) {
+                add();
+                return;
+              }
+              var i = delFrequencies.pop();
+              telnetExecute("wmx freq del " + i, client, "MT7109 (WiMax)# ", function(err, response) {
+                if (err) return callback(err);
+                del();
+              });
+            };
+            add = function() {
+              if (addFrequencies.length == 0) {
+                // commit
+                telnetExecute("commit", client, "MT7109 (WiMax)# ", function(err, response) {
+                  if (err) return callback(err);
+                  // log out
+                  telnetExecute("logout", client, null, function(err, response) {
+                    return callback(null, args);
+                  });
+                });
+                return;
+              }
+              var i = addFrequencies.pop();
+              telnetExecute("wmx freq add " + i[0] + ' ' + i[1]/1000, client, "MT7109 (WiMax)# ", function(err, response) {
+                if (err) return callback(err);
+                add();
+              });
+            };
+            del();
+          });
+        });
+      });
+    });
+  });
+};
diff --git a/custom-commands.coffee b/custom-commands.coffee
new file mode 100644
index 0000000..314fa03
--- /dev/null
+++ b/custom-commands.coffee
@@ -0,0 +1,27 @@
+config = require './config'
+common = require './common'
+
+
+exports.execute = (deviceId, command, callback) ->
+  args = command.split(/\s+/)
+  f = args.shift()
+  c = args.shift()
+
+  file = require "./config/custom_commands/#{f}"
+  file[c](deviceId, args.join(' '), callback)
+
+
+exports.getFileCommands = (filename) ->
+  commands = []
+  f = require("./config/custom_commands/#{filename}")
+  for k,v of f
+    commands.push(k)
+  return commands
+
+
+exports.getDeviceCustomCommands = (deviceId) ->
+  commands = {}
+  for k,v of config.CUSTOM_COMMANDS
+    if eval(v).test(deviceId)
+      commands[k] = exports.getFileCommands(k)
+  return commands
diff --git a/db.coffee b/db.coffee
index be9d80d..c93c2be 100644
--- a/db.coffee
+++ b/db.coffee
@@ -72,9 +72,13 @@ updateTask = (task, callback) ->
 
 
 saveTask = (task, callback) ->
-  task._id = mongodb.ObjectID(String(task._id))
-  tasksCollection.save(task, (err) ->
-    callback(err)
+  # task ID can either be a string or a MongoDB ID
+  id = String(task._id)
+  task._id = mongodb.ObjectID(id)
+  tasksCollection.save(task, (mongoErr) ->
+    memcached.del(id, (memcachedErr, res) ->
+      callback(mongoErr or memcachedErr)
+    )
   )
 
 
diff --git a/presets.coffee b/presets.coffee
index 10b12e1..9d62c0c 100644
--- a/presets.coffee
+++ b/presets.coffee
@@ -4,6 +4,7 @@ db = require './db'
 mongoQuery = require './mongo-query'
 query = require './query'
 log = require('util').log
+customCommands = require './custom-commands'
 
 
 getPresets = (callback) ->
@@ -65,6 +66,7 @@ matchObject = (object, param) ->
 
 exports.assertPresets = (deviceId, presetsHash, callback) ->
   getPresets((presets, objects) ->
+    deviceCustomCommands = customCommands.getDeviceCustomCommands(deviceId)
     # only fetch relevant params
     projection = {_id : 1}
     for p in presets
@@ -75,6 +77,10 @@ exports.assertPresets = (deviceId, presetsHash, callback) ->
         switch c.type
           when 'value', 'age'
             projection[c.name] = 1
+          when 'custom_command_value', 'custom_command_age'
+            commandfile = c.command.split(' ', 1)
+            if commandfile of deviceCustomCommands
+              projection["_customCommands.#{c.command.split(' ', 1)}"] = 1
           when 'firmware'
             projection['InternetGatewayDevice.DeviceInfo.SoftwareVersion'] = 1
           when 'add_tag', 'delete_tag'
@@ -120,6 +126,23 @@ exports.assertPresets = (deviceId, presetsHash, callback) ->
                 getParameterValues.push(c.name)
             else
               expiry = Math.min(expiry, c.age - timeDiff)
+          when 'custom_command_value'
+            [filename, commandName] = c.command.split(' ', 2)
+            continue if not deviceCustomCommands[filename]? or commandName not in deviceCustomCommands[filename]
+            currentValue = try common.getParamValueFromPath(device, "_customCommands.#{filename}")._value catch then undefined
+            dst = common.matchType(currentValue, c.value)
+            if currentValue != dst
+              taskList.push({device : deviceId, name : 'customCommand', command : c.command})
+          when 'custom_command_age'
+            [filename, commandName] = c.command.split(' ', 2)
+            continue if not deviceCustomCommands[filename]? or commandName not in deviceCustomCommands[filename]
+            command = common.getParamValueFromPath(device, "_customCommands.#{filename}")
+            timeDiff = try (now - command._timestamp) / 1000 catch then 9999999
+            if (c.age - timeDiff < config.PRESETS_TIME_PADDING)
+              expiry = Math.min(expiry, c.age)
+              taskList.push({device : deviceId, name : 'customCommand', command : c.command})
+            else
+              expiry = Math.min(expiry, c.age - timeDiff)
           when 'add_tag'
             add_tags.push(c.tag) if not device['_tags']? or c.tag not in device['_tags']
           when 'delete_tag'
@@ -200,6 +223,7 @@ getObjectHash = (object) ->
     hash += "#{k}=#{object[k]}"
   return hash
 
+
 accumulateConfigurations = (presets, objects) ->
   maxWeights = {}
   configurations = {}
diff --git a/tasks.coffee b/tasks.coffee
index 3a34cc6..cd938dd 100644
--- a/tasks.coffee
+++ b/tasks.coffee
@@ -2,13 +2,28 @@ config = require './config'
 common = require './common'
 db = require './db'
 mongodb = require 'mongodb'
+customCommands = require './custom-commands'
 BATCH_SIZE = 16
 
 exports.STATUS_QUEUED = STATUS_QUEUED = 0
 exports.STATUS_STARTED = STATUS_STARTED = 1
-exports.STATUS_PENDING = STATUS_PENDING = 2
-exports.STATUS_FAULT = STATUS_FAULT = 3
-exports.STATUS_FINISHED = STATUS_FINISHED = 4
+exports.STATUS_SAVE = STATUS_SAVE = 2
+exports.STATUS_PENDING = STATUS_PENDING = 3
+exports.STATUS_FAULT = STATUS_FAULT = 4
+exports.STATUS_FINISHED = STATUS_FINISHED = 5
+
+
+initCustomCommands = (deviceId, callback) ->
+  updates = {customCommands : []}
+  counter = 0
+  for k,v of customCommands.getDeviceCustomCommands(deviceId)
+    if 'init' in v
+      ++counter
+      customCommands.execute(deviceId, "#{k} init", (err, value) ->
+        updates.customCommands.push([k, value])
+        callback(updates) if --counter <= 0
+      )
+  callback(updates) if counter <= 0
 
 
 this.init = (task, methodResponse, callback) ->
@@ -16,7 +31,7 @@ this.init = (task, methodResponse, callback) ->
     task.subtask = {device : task.device, name : 'getParameterNames', parameterPath : '', nextLevel : false}
 
   if task.subtask.name == 'getParameterNames'
-    if methodResponse.faultcode?  
+    if methodResponse.faultcode?
       task.fault = methodResponse
       callback(null, STATUS_FAULT)
       return
@@ -42,7 +57,13 @@ this.init = (task, methodResponse, callback) ->
       # Ignore GetParameterValues errors. A workaround for the crappy Seewon devices.
       methodResponse = {parameterList : {}}
     this.getParameterValues(task.subtask, methodResponse, (err, status, cwmpResponse, deviceUpdates) ->
-      callback(err, status, cwmpResponse, deviceUpdates)
+      if status is STATUS_FINISHED
+        initCustomCommands(task.device, (updates) ->
+          common.extend(deviceUpdates, updates)
+          callback(err, status, cwmpResponse, deviceUpdates)
+        )
+      else
+        callback(err, status, cwmpResponse, deviceUpdates)
     )
   else
     throw Error('Unexpected subtask name')
@@ -241,7 +262,11 @@ this.addObject = (task, methodResponse, callback) ->
             task.subtask = {name : 'getParameterValues', parameterNames : task.parameterNames}
             subtask()
           else if status is STATUS_STARTED
-            callback(err, STATUS_STARTED, cwmpResponse, allDeviceUpdates)
+            if allDeviceUpdates.instanceName?
+              # Use STATUSS_SAVE to avoid adding duplicate object in case of error
+              callback(err, STATUS_SAVE, cwmpResponse, allDeviceUpdates)
+            else
+              callback(err, STATUS_STARTED, cwmpResponse, allDeviceUpdates)
           else
             throw Error('Unexpected subtask status')
         )
@@ -343,5 +368,17 @@ this.download = (task, methodResponse, callback) ->
     callback(null, STATUS_FINISHED)
 
 
+this.customCommand = (task, methodResponse, callback) ->
+  # TODO implement timeout
+  customCommands.execute(task.device, task.command, (err, value) ->
+    if err?
+      task.fault = err
+      callback(null, STATUS_FAULT)
+    else
+      commandName = task.command.split(' ', 2)[0]
+      callback(null, STATUS_FINISHED, null, {customCommands : [[commandName, value]]})
+  )
+
+
 exports.task = (task, methodResponse, callback) ->
   this[task.name](task, methodResponse, callback)