diff --git a/nix/module.nix b/nix/module.nix
index 224c29c..494335b 100644
--- a/nix/module.nix
+++ b/nix/module.nix
@@ -112,6 +112,10 @@ in {
     };
 
     systemd.services."pi-air-quality-monitor" = let
+      globalEnv = pkgs.writeText "global.env" ''
+        SERIAL_DEVICE=${cfg.settings.serialPort}
+      '';
+
       redisEnv = pkgs.writeText "redis.env" ''
         REDIS_HOST=${cfg.settings.redis.host}
         REDIS_PORT=${toString cfg.settings.redis.port}
@@ -125,7 +129,11 @@ in {
         Type = "simple";
         User = cfg.settings.user;
         Group = cfg.settings.group;
-        EnvironmentFile = [redisEnv] ++ optional (cfg.settings.environmentFile != null) cfg.settings.environmentFile;
+        EnvironmentFile = lib.concatLists [
+          [globalEnv]
+          (optional (cfg.settings.environmentFile != null) [cfg.settings.environmentFile])
+          (optional cfg.settings.redis.createLocally [redisEnv])
+        ];
         WorkingDirectory = "${cfg.settings.dataDir}";
         ExecStart = "${lib.getExe cfg.package}";
         Restart = "always";
diff --git a/nix/tests/checks/basic.nix b/nix/tests/checks/basic.nix
index 745c0c1..5370156 100644
--- a/nix/tests/checks/basic.nix
+++ b/nix/tests/checks/basic.nix
@@ -57,18 +57,17 @@ in
       log.info("Check if unit is running correctly")
       server.wait_for_unit("pi-air-quality-monitor.service")
       server.succeed("systemctl status pi-air-quality-monitor.service | grep 'Active: active (running)' >&2")
-      server.succeed("journalctl -u pi-air-quality-monitor.service >&2")
+      server.fail("journalctl -u pi-air-quality-monitor.service | grep 'RuntimeError'")
 
       log.info("Showing units content")
       server.succeed("systemctl status pi-air-quality-monitor.service >&2")
       server.succeed("systemctl cat pi-air-quality-monitor.service >&2")
-      server.succeed("systemctl cat pi-air-quality-monitor.socket >&2")
 
       log.info("Checking if service is accessible locally")
       server.succeed("nc -vz localhost 8080")
 
       client.start()
       client.wait_for_unit("default.target")
-      #client.succeed("nc -vz server 8080")
+      client.succeed("nc -vz server 8080")
     '';
   }