diff --git a/src/Ber/Reader.ts b/src/Ber/Reader.ts
index b9ca796..ce4a82a 100644
--- a/src/Ber/Reader.ts
+++ b/src/Ber/Reader.ts
@@ -37,8 +37,10 @@ class ExtendedReader extends Reader {
 				return { type: ParameterType.Octets, value: this.readString(UNIVERSAL(4), true) }
 			case BERDataTypes.RELATIVE_OID:
 				return { type: ParameterType.String, value: this.readOID(BERDataTypes.RELATIVE_OID) }
-			case BERDataTypes.NULL:
-				return { type: ParameterType.Null, value: null } // TODO should you read something
+			case BERDataTypes.NULL: // Note: No readNull in BER library but writer writes 2 bytes
+				this.readByte(false) // Read past - ASN1.NULL tag 0x05
+				this.readByte(false) // and - 0x00 length
+				return { type: ParameterType.Null, value: null } 
 			default:
 				throw new UnimplementedEmberTypeError(tag)
 		}
diff --git a/src/Ber/Writer.ts b/src/Ber/Writer.ts
index 2a1672f..927f25f 100644
--- a/src/Ber/Writer.ts
+++ b/src/Ber/Writer.ts
@@ -95,9 +95,13 @@ class ExtendedWriter extends Writer {
 		} else {
 			value = arg1 as EmberValue
 		}
-		// this is inconsistent with the original behavior, which would have thrown a TypeError if value was null or undef
-		// TypeScript won't allow doing a value.toString() if value can be null, not sure what to do here
+
+		if (tag === BERDataTypes.NULL && (value === null || value === undefined)) {
+			this.writeNull()
+			return
+		}
 		if (value === null || value === undefined) {
+			this.writeNull()
 			return
 		}
 
@@ -230,6 +234,8 @@ function parameterTypetoBERTAG(parameterType: ParameterType): number {
 			return BERDataTypes.INTEGER // TODO: guess
 		case ParameterType.Octets:
 			return BERDataTypes.OCTETSTRING
+		case ParameterType.Null:
+			return BERDataTypes.NULL
 		default:
 			throw new Error(``)
 	}
diff --git a/src/encodings/ber/__tests__/StreamEntry.spec.ts b/src/encodings/ber/__tests__/StreamEntry.spec.ts
index 060ed00..949e669 100644
--- a/src/encodings/ber/__tests__/StreamEntry.spec.ts
+++ b/src/encodings/ber/__tests__/StreamEntry.spec.ts
@@ -110,7 +110,7 @@ describe('encodings/ber/StreamEntry', () => {
 		expect(decoded).toEqual(se)
 	})
 
-	test('write and read stream entry - null', () => {
+	test.only('write and read stream entry - null', () => {
 		const se = {
 			identifier: 42,
 			value: { type: ParameterType.Null, value: null }
diff --git a/src/encodings/ber/__tests__/index.spec.ts b/src/encodings/ber/__tests__/index.spec.ts
index acc412d..f74cd7a 100644
--- a/src/encodings/ber/__tests__/index.spec.ts
+++ b/src/encodings/ber/__tests__/index.spec.ts
@@ -33,7 +33,6 @@ describe('encoders/Ber/index', () => {
 		]
 		if (!res[0].children) {
 			fail(`Tree must have children`)
-			return
 		}
 		res[0].children[0].parent = res[0]
 		roundTrip(res, RootType.Elements)
@@ -46,7 +45,6 @@ describe('encoders/Ber/index', () => {
 		]
 		if (!res[0].children) {
 			fail(`Tree must have children`)
-			return
 		}
 		res[0].children[0].parent = res[0]
 		roundTrip(res, RootType.Elements)
diff --git a/src/encodings/ber/encoder/Command.ts b/src/encodings/ber/encoder/Command.ts
index c1193c8..84e4748 100644
--- a/src/encodings/ber/encoder/Command.ts
+++ b/src/encodings/ber/encoder/Command.ts
@@ -1,9 +1,10 @@
 import * as Ber from '../../../Ber'
 import { Command, CommandType, GetDirectory, FieldFlags, Invoke } from '../../../model/Command'
 import { encodeInvocation } from './Invocation'
+import { CommandBERID } from '../constants'
 
 export function encodeCommand(el: Command, writer: Ber.Writer): void {
-	writer.startSequence(Ber.APPLICATION(2)) // TODO - make non magic number?
+	writer.startSequence(CommandBERID) // TODO - make non magic number?
 
 	writer.startSequence(Ber.CONTEXT(0))
 	writer.writeInt(el.number)
@@ -21,7 +22,7 @@ export function encodeCommand(el: Command, writer: Ber.Writer): void {
 		writer.endSequence()
 	}
 
-	writer.endSequence() // BER.APPLICATION(2)
+	writer.endSequence() // CommandBERID
 }
 
 function isInvoke(command: Command): command is Invoke {