diff --git a/vocode/models/telephony.py b/vocode/models/telephony.py
index a1a0a4d..1bf57ec 100644
--- a/vocode/models/telephony.py
+++ b/vocode/models/telephony.py
@@ -1,15 +1,21 @@
+from typing import Optional
 from vocode.models.model import BaseModel
 from vocode.models.agent import AgentConfig
+from vocode.models.synthesizer import SynthesizerConfig
+
 
 class CallEntity(BaseModel):
     phone_number: str
 
+
 class CreateInboundCall(BaseModel):
     agent_config: AgentConfig
     twilio_sid: str
 
+
 class CreateOutboundCall(BaseModel):
     recipient: CallEntity
     caller: CallEntity
-    agent_config: AgentConfig 
+    agent_config: AgentConfig
+    synthesizer_config: Optional[SynthesizerConfig] = None
     # TODO add IVR/etc.