Grandstream HandyTone 503 BT (UK) Caller ID / Display Settings

After fiddling with the settings for Caller ID on my FXO port, I finally found something that works:

Caller ID Scheme: SIN 227 – BT
FSK Caller ID Minimum RX Level (dB): -40
FSK Caller ID Seizure Bits: 96
FSK Caller ID Mark Bits: 55
Caller ID Transport Type: Relay via SIP From

If you have a Grandstream HandyTone 503 connected to a BT line on the FXO port then leave your configuration tips below!

3 thoughts on “Grandstream HandyTone 503 BT (UK) Caller ID / Display Settings

  1. Con Blackett

    This helped a LOT. However I also found after a lot of experimentation that in the UK you need to set the PSTN Disconnect Tone to f1=400@-20,f2=400@-20,c=0/0; on the 503. Otherwise the call intermittently hangs up the device and you need to reboot it to release the PSTN line 🙂


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