With the removal of copper lines from our street I have had to switch my Spark provided home-office landline number, to a VOIP service.

Worldnet, my fibre ISP, supplied a Linskys PAP2NA ATA box and arranged the porting of my landline number to VOIP. All works.

When I am away from my home-office I always diverted my copper landline number to my cellphone, and I am also able to to that with the now installed VOIP service. 

However, with the VOIP service, when a call is forwarded to my cellphone it no longer displays the caller ID on my cellphone (it used to always do this with my copper line service).

I asked Worldnet about this and they said Caller-ID on Call Diversion was not possible but gave no explantion why, and there are almost no native English speakers in their IT department to discuss this with.

Are there any technicians on Geekzone that can explain why it is not possible for me to have Caller-ID displayed when diverting the number to my cellphone (it does display the caller ID on the phone at home when no diversion is in place). I would have imagined this would be a software coding issue to implement, afterall they've always manage to every month charge me for the calls minutes that are diverted through to my cellphone?

It's only being without the caller ID that I realised how useful it is, now that I don't have it!