Mrs Almasy-
If you are planning on having multiple dictators "call in" or dictate, your best bet would either be to purchase the small dictation server, or to look into digital handheld portables. There are telephone recorders, but only take calls one at a time...unless someone knows something out there that may work. *let me know!*
Digital handheld recorders work well because you can send the voice files through Email, to an FTP site, or even to a network folder if you are in a company. Another bonus is there are softwares that can encrypt those voice files to be HIPAA compliant which is a good thing.
Hopefully this helps and answers your questions!