diff --git a/config/custom_commands/seowon_frequencies.js b/config/custom_commands/seowon_frequencies.js
new file mode 100644
index 0000000..6a2d37e
--- /dev/null
+++ b/config/custom_commands/seowon_frequencies.js
@@ -0,0 +1,188 @@
+// 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 host = '192.168.1.1';
+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(response) {
+      // enter password
+      telnetExecute(PASSWORD, client, "MT7109> ", function(response) {
+        callback(client);
+      });
+    });
+  });
+ return client;
+}
+
+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) {
+      connection.removeListener('data', listener);
+      callback(response.slice(command.length, 0 - prompt.length));
+    }
+  };
+
+  var end = function() {
+    connection.removeListener('end', end);
+    callback(response.slice(command.length));
+  };
+
+  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);
+    callback(url.hostname);
+  });
+};
+
+exports.init = function(deviceId, args, callback) {
+  exports.get(deviceId, args, callback);
+};
+
+exports.get = function(deviceId, args, callback) {
+  var currentFrequencies = [];
+
+  getDeviceIp(deviceId, function(ip) {
+    var client = telnetConnect(ip, function() {
+      // enter privileged mode
+      telnetExecute("enable", client, "MT7109# ", function(response) {
+        // show frequencies
+        telnetExecute("show wmx freq", client, "MT7109# ", function(response) {
+          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);
+          }
+          // exist privileged mode
+          telnetExecute("exit", client, "MT7109> ", function(response) {
+            // log out
+            telnetExecute("logout", client, null, function(response) {
+              callback(null, currentFrequencies.join(','));
+            });
+          });
+        });
+      });
+    });
+  });
+};
+
+exports.set = function(deviceId, args, callback) {
+  var newFrequencies = parseFrequencies(args);
+  var addFrequencies = [];
+  var delFrequencies = [];
+
+  getDeviceIp(deviceId, function(ip) {
+    var client = telnetConnect(ip, function() {
+      // enter privileged mode
+      telnetExecute("enable", client, "MT7109# ", function(response) {
+        // show frequencies
+        telnetExecute("show wmx freq", client, "MT7109# ", function(response) {
+          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) {
+            // exit privileged mode
+            telnetExecute("exit", client, "MT7109> ", function(response) {
+              // log out
+              telnetExecute("logout", client, null, function(response) {
+                callback(null, args);
+              });
+            });
+            return;
+          }
+
+          telnetExecute("wimax", client, "MT7109 (WiMax)# ", function(response) {
+            var add, del;
+            del = function() {
+              if (delFrequencies.length == 0) {
+                add();
+                return;
+              }
+              var i = delFrequencies.pop();
+              telnetExecute("wmx freq del " + i, client, "MT7109 (WiMax)# ", function(response) {
+                del();
+              });
+            };
+            add = function() {
+              if (addFrequencies.length == 0) {
+                // commit
+                telnetExecute("commit", client, "MT7109 (WiMax)# ", function(response) {
+                  // exist wimax mode
+                  telnetExecute("exit", client, "MT7109# ", function(response) {
+                    // exit privileged mode
+                    telnetExecute("exit", client, "MT7109> ", function(response) {
+                      // log out
+                      telnetExecute("logout", client, null, function(response) {
+                        callback(null, args);
+                      });
+                    });
+                  });
+                });
+                return;
+              }
+              var i = addFrequencies.pop();
+              telnetExecute("wmx freq add " + i[0] + ' ' + i[1]/1000, client, "MT7109 (WiMax)# ", function(response) {
+                add();
+              });
+            };
+            del();
+          });
+        });
+      });
+    });
+  });
+};