Most modern venues will have Wi-Fi internet connectivity and / or some system for getting online access. In some instances this is included whereas in other cases it is an extra. Likewise most venues will support good cellular reception but it is possible that you might need alternative or land line access. Exhibitor manuals will detail availability, options available and pricing.  It is more likely that you will have difficulties with your hotel communication than at a modern venue however as with all these things if you know you need LAN access for example, that you make provision with the organisers directly.