Voice Communications Requirements

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Communication Forwarding

In order to support Caregivers calling in-bound to the Central Monitoring room, forwarding is required. Call forwarding, or call diversion, is a telephony feature of hospitals telephone switching systems which redirects a telephone call to another destination. The existing direct dial phone number of central monitoring unit or group will need to be forwarded to new phone number provided by Spacelabs SafeNSound. Forwarding this number allows the inbound call to reach the SafeNSound desktop client, ring and become answered by a Monitor Technician. We also request central monitoring unit or group be assigned to a new call group with a direct dial number to be used as backup inbound call method. This supports Quick Messages as well as Voice Calls.


Step 1.

Hospital forwards existing Desk Phone number to SnS Twilio .

Typically, this is a VoIP phone with a virtually assigned phone number This can be lifted off the phone and replaced by a new phone number in step 2.

Step 2.

Hospital replaces the Desk Phone with a new number.

This allows calls to flow into SnS as well as missed calls to flow to a backup number that utilizes the new desk phone number. The hospital’s Tele-Communications contact will need to be engaged to accomplish this task.


Flow Diagram:

mt to caregiver.JPGcaregiver to mt.JPG

Communication Networking and Firewall

SafeNSound utilizes Twilio to programmatically make and receive phone calls. Please insure all IP’s and Ports listed below are open on the monitor technician PC’s. This is required for the communications to work properly. Not applying this configuration could delay communications or cause a complete failure:

Twilio Voice SDK Private Edge Locations


Voice Media Server Connectivity Requirements

Secure Media (ICE/STUN/SRTP) Edge Locations Protocol Source IP Source Port † Destination IP Ranges Destination Port Range
roaming (gll) UDP ANY ANY 10,000 - 60,000

† The SDK will select any available port from the ephemeral range. On most machines, this means the port range 1,024 to 65,535.


Signaling Connectivity Requirements

  Your Intranet Allowed destinations  
  Protocol Source IP Source Port † Destination Destination Port
Voice JavaScript SDK          
Secure TLS connection to Twilio signalling Gateway TCP ANY ANY




Secure TLS Insights logging gateway TCP ANY ANY eventgw.twilio.com 443
Mobile Voice SDKs          
Secure TLS connection to Twilio GLL Signalling Gateway TCP ANY ANY chunderm.gll.twilio.com 443
Secure TLS to Insights Gateway TCP ANY ANY eventgw.twilio.com 443
Secure TLS to Registration Server TCP ANY ANY ers.twilio.com 443

† The client will select any available port from the ephemeral range. On most machines, this means the port range 1,024 to 65,535.


Network Bandwidth Requirements

Bandwidth (Uplink/Downlink) Opus*: 40kbps / 40kbps
PCMU: 100kbps / 100kbps
Latency (RTT) < 200ms
Jitter < 30ms
Packet Loss < 3%

* Opus is the default codec for Mobile.



Network Diagnostics and Testing

If you're experiencing issues with calling here are some steps you can take to diagnose the problem:

1. On the caregiver's workstation go to https://networktest.twilio.com/ and ensure all voice tests pass.

2. Check Your Internet Connection: Ensure that your internet connection is stable and working properly.

3. Restart Your Device: Sometimes, simply restarting your computer or device can resolve connectivity issues.



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