Newer type fiber modem with built‑in WiFi
For customers having a fiber modem with router functionality and built‑in WiFi, there is no limit to how many PCs or other network devices that can be connected to the modem.

Older type fiber modem without built‑in WiFi
If you have an older type of fiber modem without built‑in WiFi, you can only connect one PC directly to the modem.
If you want to connect multiple PCs and other network devices, you must first connect a wireless router to the fiber modem, and then connect all the other devices to that router. The reason for that is, this type of fiber modem does not include router functionality and every customer only get one single public IP address. This means, if you connect a PC directly to the fiber modem, that PC receives the IP address and is the only device with access to the Internet. If you instead connect a wireless router to the fiber modem, the router receives the IP address - and then the router is connected to the Internet and provides internet access to all devices connected to it.