OC Transpo buses will be equipped with a new tone for the "next stop" announcement starting Sunday.

The new tone is designed to sound different from the bell that signifies a requested stop. Some riders have complained that the current similarity between the two sounds makes it difficult to tell if a stop has been requested, causing many to miss their stops.

The new tone is part of an overhaul of stop-calling technology that began in the summer when an automated next-stop announcement system was added to some of the OC Transpo fleet.

All buses are scheduled to be equipped with the automated system by the end of March, a month later than what was initially planned.