Hash Key not recognised

[chris623]

Trying to log on to on line NSANDI with mobile Apple SE to verify account. They do not recognise the sound of the Hash Key. What can I do about this?

[caesarome]

@chris623 

Try contacting them to see what they suggest ?

[63johnw]

Hi @chris623  is your firmware up to to date ?

[chris623]

Firmware is up to date NSandI think it is a software issue with mobile network. I am trying to contact them but to contact them I also needed to press Hash key !

[PandJ2020]

DTMF tones are generated by the sending device - they are then transported over the cellular network to NS&I.

A quick Google shows others have had the exact issue sending this tone.  (One post even suggested it's NS&I's policy to say it isn't their issue)

Some suggestions include hanging up and trying again as it works 'about 50% of the time'.

One possibility is the quality of the audio transmission over the cellular network.  If the signal is overly-compressed (possibly due to limited bandwidth) then the destination may not recognise the tone.

Worth trying switching to WiFi calling (or vice versa if on) and seeing if a clearer tone is received.  DTMF uses Internationally standard tones.