‘Unknown’ Caller ID issue in Grandstream ATA HT813

Grandstream HT813 Unknown CallerID

Description

This article suggests the settings for resolving the common issue – Unknown Caller ID in Grandstream ATA HT813. These parameters can be found under the FXO Port Page.

1. Adjust the Number of Rings from 1 to 4

2. Configure Caller ID Transport Type to Relay via P-Asserted-Identity if it is unable to detect inbound calls.

3. Test with all Caller ID Scheme

4. Toggle the AC termination model to Auto-detect. The default is the U.S.A.

5. Increase FSK Caller ID Minimum RX Level, save and apply followed by a reboot

6. Configure PSTN Ring Timeout (sec) to 10 (inbound call detection)

7. Configure PSTN Ring Thru Delay (sec) to 10.

Loop Current Disconnect

When the far end hangs up, the Telco will send the local side loop current disconnect signal to the phone.  The Telco disconnects the line for some time (about 300ms) and then reconnects the line. 

On the other hand, some COs work differently.  They require that the loop current disconnect be enabled on the FXO side because the CO expects the user to hang up the phone when the call is terminated (on either side).  So, when using HT813, the CO still considers it as a phone with the ability to hang up.  

However, the ability to hang up is not built in the HT813, and most FXO gateways so they expect the CO to disconnect the line.  That is why Loop Current Disconnect on FXO ports is enabled by default. There is no guarantee that the CO will disconnect the call because there is no disconnect ‘supervision’ from the side of the COs.  

The most common problem is getting a busy dial tone on the phone even when the call has ended.