SCSI: none
Serial Ports: 1
Sound Output: mono 8 bit.
ADB: see below
Ethernet: see below
Machine Gestalt ID: 102
PRAM Battery: service center replacement only

Minutiae:

Apple sometimes advertises this as a 66 MHz machine, since the clock speed is doubled inside the processor chip.  However, all I/O to the processor is done at 33 MHz. 

9” active matrix LCD - 4 bit (16 grays) Display.

Has a 152-pin PDS (Processor Direct Slot) connector for connecting to the Duo Docks.

Serial Port with the phone icon supports synchronous modems, with handshaking on both the output and input.

Has 1 MB ROM.