The modem is a cherised hand-down, but like many hand-downs it had its quirks. It came with dead speaker. I was in a hurry to get it working (and poor), so rather than buy a spare, I drilled the shield, wired an old 3.5mm jack and used an external speaker cone I'd mounted on a cardboard box.
This is an internal ISA bus modem, so it contains both a Hayes-compatible smart modem and a serial port adaptor for it. The white stickered chip in the foreground is almost certainly an Intel 8250 UART. The smaller one is a fully integrated serial smart modem controller. I mean, yes, there was large scale integration. It was the 90s, we weren't total savages.
the two smaller black packages on the left side are the address decoders that mapped the UART to COM1 or COM2. You set that using the two jumpers.