diff --git a/modem_simple_proxy.cc b/modem_simple_proxy.cc
index 37c9c83..a902b16 100644
--- a/modem_simple_proxy.cc
+++ b/modem_simple_proxy.cc
@@ -1,33 +1,58 @@
-// Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+// Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "shill/modem_simple_proxy.h"
 
+#include "shill/cellular_error.h"
+#include "shill/error.h"
+
 using std::string;
 
 namespace shill {
 
-ModemSimpleProxy::ModemSimpleProxy(DBus::Connection *connection,
+ModemSimpleProxy::ModemSimpleProxy(ModemSimpleProxyDelegate *delegate,
+                                   DBus::Connection *connection,
                                    const string &path,
                                    const string &service)
-    : proxy_(connection, path, service) {}
+    : proxy_(delegate, connection, path, service) {}
 
 ModemSimpleProxy::~ModemSimpleProxy() {}
 
-DBusPropertiesMap ModemSimpleProxy::GetStatus() {
-  return proxy_.GetStatus();
+void ModemSimpleProxy::GetModemStatus(AsyncCallHandler *call_handler,
+                                      int timeout) {
+  proxy_.GetStatus(call_handler, timeout);
 }
 
-void ModemSimpleProxy::Connect(const DBusPropertiesMap &properties) {
-  proxy_.Connect(properties);
+void ModemSimpleProxy::Connect(const DBusPropertiesMap &properties,
+                               AsyncCallHandler *call_handler, int timeout) {
+  proxy_.Connect(properties, call_handler, timeout);
 }
 
-ModemSimpleProxy::Proxy::Proxy(DBus::Connection *connection,
+ModemSimpleProxy::Proxy::Proxy(ModemSimpleProxyDelegate *delegate,
+                               DBus::Connection *connection,
                                const string &path,
                                const string &service)
-    : DBus::ObjectProxy(*connection, path, service.c_str()) {}
+    : DBus::ObjectProxy(*connection, path, service.c_str()),
+      delegate_(delegate) {}
 
 ModemSimpleProxy::Proxy::~Proxy() {}
 
+void ModemSimpleProxy::Proxy::GetStatusCallback(const DBusPropertiesMap &props,
+                                                const DBus::Error &dberror,
+                                                void *data) {
+  AsyncCallHandler *call_handler = reinterpret_cast<AsyncCallHandler *>(data);
+  Error error;
+  CellularError::FromDBusError(dberror, &error);
+  delegate_->OnGetModemStatusCallback(props, error, call_handler);
+}
+
+void ModemSimpleProxy::Proxy::ConnectCallback(const DBus::Error &dberror,
+                                              void *data) {
+  AsyncCallHandler *call_handler = reinterpret_cast<AsyncCallHandler *>(data);
+  Error error;
+  CellularError::FromDBusError(dberror, &error);
+  delegate_->OnConnectCallback(error, call_handler);
+}
+
 }  // namespace shill