Asus P8Z77-V PRO/THUNDERBOLT - Manual (Page 56)

2-32 Chapter 2: Hardware information
Chapter 2
11. Serial port connectors (10-1 pin COM1)
The connector is for a serial (COM) port. Connect the serial port module cable to the
connector, then install the module to a slot opening at the back of the system chassis.
The serial port bracket (COM1) is purchased separately.
12. TPM connector (20-1 pin TPM)
This connector supports a Trusted Platform Module (TPM) system, which can securely
store keys, digital certificates, passwords, and data. A TPM system also helps enhance
network security, protects digital identities, and ensures platform integrity.
TPM module is purchased separately.