Please be aware it is the losing carrier (where the numbers are being ported from) that determines whether a service is 'simple' or 'complex', however this should clarify things for most services.
The best way to determine if your port involves 'complex' services is to check the itemized services and charges section of your customer's latest phone bill.
Category A ('simple services')
A 'simple service' is generally any single stanadlone PSTN service or standalone VoIP line (such as those that come bundled with home and small business internet plans). Most residential lines are simple services. Many standalone fax, alarm and ADSL lines are also simple services.
Having ADSL attached will not make a PSTN line a 'complex' service (though porting the number will terminate the ADSL service).
Category C ('complex services')
Any 'complex service' will require a Category C port. A 'complex service' involves a batch of numbers or single lines with certain features added.
Any PSTN service with the following features will be considered 'complex':
- MSN/Faxstream Duet
- Enhanced Faxstream
- Siteline
- Line Hunt
- Analogue Indial
Any ISDN services (ISDN2, Onramp2, Onramp10/20/30) will have multiple numbers and are 'complex' services.
Most SIP trunks and hosted PBX (Telstra DoT, Commander Phone) will be 'complex' services.