Netopia 435 Reference Manual page 12

Introduction 1-5
You may want to attach a PC Card modem to the Netopia ISDN Router
to remotely configure it or to upgrade its firmware (see "To update
Netopia's firmware" on page 10-17.)
Follow the manufacturer's instructions when unpacking and preparing
to use the PC Card modem. A telephone cable should be included with
your modem. One end of the cable connects to your modem, while the
PC Card
(PCMCIA)
other end (RJ-11) connects to an analog telephone line wall socket
( not an ISDN line)
.