I'm not sure all of the models that use the 425A network, with the C2A Ringer, so I just listed it as 500.
Please P.M. with a list if you know.
Paul F, tells me the following 500 sets came with the 425A Network, How many had C2A ringers of the following is to be determined.
500
500T
500A, 500B
500J, 500K
501
501T
501A, 501B
501J, 501K
D/P