diff --git a/reactor-plc/configure.lua b/reactor-plc/configure.lua
index 1f7fa68..e19ebfb 100644
--- a/reactor-plc/configure.lua
+++ b/reactor-plc/configure.lua
@@ -83,7 +83,7 @@ local tmp_cfg = {
     ConnTimeout = nil,      ---@type number
     WiredModem = false,     ---@type string|false
     TrustedRange = nil,     ---@type number
-    AuthKey = "",           ---@type string
+    AuthKey = nil,          ---@type string|nil
     LogMode = 0,            ---@type LOG_MODE
     LogPath = "",
     LogDebug = false,
diff --git a/scada-common/ppm.lua b/scada-common/ppm.lua
index 6feed0d..aa46808 100644
--- a/scada-common/ppm.lua
+++ b/scada-common/ppm.lua
@@ -453,7 +453,7 @@ function ppm.get_fission_reactor() return ppm.get_device("fissionReactorLogicAda
 ---@return Modem|nil modem function table
 function ppm.get_modem(iface)
     local modem  = nil
-    local device = ppm_sys.mounts[iface]
+    local device = _ppm.mounts[iface]
 
     if device and device.type == "modem" then modem = device.dev end
 
@@ -485,7 +485,7 @@ end
 function ppm.get_wired_modem_list()
     local list = {}
 
-    for iface, device in pairs(ppm_sys.mounts) do
+    for iface, device in pairs(_ppm.mounts) do
         if device.type == "modem" and not device.dev.isWireless() then list[iface] = device end
     end