e4d47c27__DataSheet_for_product_XE2422H__description
[pin] 5 [name] /RI [description] 
The /RI signal reports on the presence of an incoming ring signal. When a ring occurs across Tip and Ring, the /RI output goes low and toggles with the cadence of the ring signal. /RI is controlled by register S0D bit 6. The default condition is for /RI to be disabled.
Cermetek DataSheet for product XE2422H
description