diff --git a/src/source-discovery.ts b/src/source-discovery.ts
index aeec3b8..6effc05 100644
--- a/src/source-discovery.ts
+++ b/src/source-discovery.ts
@@ -4,7 +4,7 @@ import {
   GatewaySession,
 } from './gateway-session'
 import { GatewayRequest, Item, Query, QueryMethod } from './protobuf'
-import { getUniqueAttributeValue, newDuration } from './util'
+import { getUniqueAttributeValue, newDeadline } from './util'
 
 export enum DiscoveryField {
   TYPE = 0,
@@ -111,7 +111,7 @@ export class SourceDiscovery extends EventTarget {
         value: new Query({
           scope: 'global',
           method: QueryMethod.LIST,
-          timeout: newDuration(5000),
+          deadline: newDeadline(5000),
           UUID: parse(v4()),
           type,
         }),
diff --git a/src/util.ts b/src/util.ts
index 44dab87..bb21c97 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -57,6 +57,17 @@ export function newDuration(ms: number): Duration {
   return d
 }
 
+/**
+ * Converts a number of milliseconds to a protobuf Timestamp that number of milliseconds in the future.
+ *
+ * @param ms The number of milliseconds
+ * @returns A timestamp in protobuf format
+ */
+export function newDeadline(ms: number): Timestamp {
+  const deadline = new Date(Date.now() + ms)
+  return Timestamp.fromDate(deadline)
+}
+
 /**
  * Gets the value of a particular attribute. *Note:* that this only supports
  * attributes at the top level currently