diff --git a/homeassistant/components/elkm1/alarm_control_panel.py b/homeassistant/components/elkm1/alarm_control_panel.py
index b925026bfaa..c3ed6bbc40d 100644
--- a/homeassistant/components/elkm1/alarm_control_panel.py
+++ b/homeassistant/components/elkm1/alarm_control_panel.py
@@ -14,7 +14,6 @@ from homeassistant.components.alarm_control_panel.const import (
     SUPPORT_ALARM_ARM_NIGHT,
 )
 from homeassistant.const import (
-    ATTR_ENTITY_ID,
     STATE_ALARM_ARMED_AWAY,
     STATE_ALARM_ARMED_HOME,
     STATE_ALARM_ARMED_NIGHT,
@@ -36,18 +35,15 @@ from .const import (
     ELK_USER_CODE_SERVICE_SCHEMA,
 )
 
-DISPLAY_MESSAGE_SERVICE_SCHEMA = vol.Schema(
-    {
-        vol.Optional(ATTR_ENTITY_ID, default=[]): cv.entity_ids,
-        vol.Optional("clear", default=2): vol.All(vol.Coerce(int), vol.In([0, 1, 2])),
-        vol.Optional("beep", default=False): cv.boolean,
-        vol.Optional("timeout", default=0): vol.All(
-            vol.Coerce(int), vol.Range(min=0, max=65535)
-        ),
-        vol.Optional("line1", default=""): cv.string,
-        vol.Optional("line2", default=""): cv.string,
-    }
-)
+DISPLAY_MESSAGE_SERVICE_SCHEMA = {
+    vol.Optional("clear", default=2): vol.All(vol.Coerce(int), vol.In([0, 1, 2])),
+    vol.Optional("beep", default=False): cv.boolean,
+    vol.Optional("timeout", default=0): vol.All(
+        vol.Coerce(int), vol.Range(min=0, max=65535)
+    ),
+    vol.Optional("line1", default=""): cv.string,
+    vol.Optional("line2", default=""): cv.string,
+}
 
 SERVICE_ALARM_DISPLAY_MESSAGE = "alarm_display_message"
 SERVICE_ALARM_ARM_VACATION = "alarm_arm_vacation"