diff --git a/src/phonebook/dectutils.py b/src/phonebook/dectutils.py
index 7be4eff4..957fb330 100644
--- a/src/phonebook/dectutils.py
+++ b/src/phonebook/dectutils.py
@@ -9,14 +9,16 @@ class DectUtils:
     """
 
     DECT_MATRIX = {
-        "2": ["A", "B", "C"],
-        "3": ["D", "E", "F"],
-        "4": ["G", "H", "I"],
-        "5": ["J", "K", "L"],
-        "6": ["M", "N", "O"],
-        "7": ["P", "Q", "R", "S"],
-        "8": ["T", "U", "V"],
-        "9": ["W", "X", "Y", "Z"],
+        "0": ["0"],
+        "1": ["1"],
+        "2": ["2", "A", "B", "C"],
+        "3": ["3", "D", "E", "F"],
+        "4": ["4", "G", "H", "I"],
+        "5": ["5", "J", "K", "L"],
+        "6": ["6", "M", "N", "O"],
+        "7": ["7", "P", "Q", "R", "S"],
+        "8": ["8", "T", "U", "V"],
+        "9": ["9", "W", "X", "Y", "Z"],
     }
 
     def __init__(self):
@@ -32,11 +34,6 @@ class DectUtils:
         """
         Generator to recursively get all combinations of letters for this number
         """
-        if "0" in numbers or "1" in numbers:
-            logger.error(
-                "Numbers with 0 or 1 in them are not expressible as letters, bail out"
-            )
-            return False
         # loop over the possible letters for the first digit
         for letter in self.DECT_MATRIX[numbers[0]]:
             # if we have more digits..
diff --git a/src/phonebook/migrations/0002_auto_20200310_1902.py b/src/phonebook/migrations/0002_auto_20200310_1902.py
new file mode 100644
index 00000000..90e39808
--- /dev/null
+++ b/src/phonebook/migrations/0002_auto_20200310_1902.py
@@ -0,0 +1,37 @@
+# Generated by Django 3.0.3 on 2020-03-10 18:02
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("phonebook", "0001_initial"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="dectregistration",
+            name="description",
+            field=models.TextField(
+                blank=True,
+                help_text="Description of this registration, like a name/handle, or a location or service name.",
+            ),
+        ),
+        migrations.AlterField(
+            model_name="dectregistration",
+            name="letters",
+            field=models.CharField(
+                blank=True,
+                help_text="The letters or numbers chosen to represent this DECT number in the phonebook. Optional.",
+                max_length=9,
+            ),
+        ),
+        migrations.AlterField(
+            model_name="dectregistration",
+            name="number",
+            field=models.CharField(
+                help_text="The DECT phonenumber, four digits or more.", max_length=9
+            ),
+        ),
+    ]
diff --git a/src/phonebook/models.py b/src/phonebook/models.py
index 79f78911..3e4147cf 100644
--- a/src/phonebook/models.py
+++ b/src/phonebook/models.py
@@ -29,18 +29,18 @@ class DectRegistration(CampRelatedModel):
     )
 
     number = models.CharField(
-        max_length=9, help_text="The DECT number, numeric or as letters",
+        max_length=9, help_text="The DECT phonenumber, four digits or more.",
     )
 
     letters = models.CharField(
         max_length=9,
         blank=True,
-        help_text="The letters chosen to represent this DECT number in the phonebook. Optional.",
+        help_text="The letters or numbers chosen to represent this DECT number in the phonebook. Optional.",
     )
 
     description = models.TextField(
         blank=True,
-        help_text="Description of this registration, like a name or a location or a service.",
+        help_text="Description of this registration, like a name/handle, or a location or service name.",
     )
 
     activation_code = models.CharField(
@@ -65,6 +65,12 @@ class DectRegistration(CampRelatedModel):
         This code really belongs in model.clean(), but that gets called before form_valid()
         which is where we set the Camp object for the model instance.
         """
+        # First of all, check that number is numeric
+        try:
+            int(self.number)
+        except ValueError:
+            raise ValidationError("Phonenumber must be numeric!")
+
         # check for conflicts with the same number
         if (
             DectRegistration.objects.filter(camp=self.camp, number=self.number)