Allied Telesis AT-8550SP - Manual (Page 30)

Chapter 1: Overview
30
Module Expansion Slots
The AT-8516F/SC, AT-8524M, and AT-8524POE switches have two
expansion slots. Each slot can accommodate an expansion module. You
can use the slots to add 100Base and 1000Base fiber optic and twisted
pair ports to the switch.
Note
For a list of the Allied Telesis expansion modules supported by the
switches, contact your Allied Telesis sales representative or refer to
our web site at: www.alliedtelesis.com.