Motorola 9645 Modem compatability

Please,

Does anyone know if there is a currently available, compatible modem for the Motorola 9645 4 wire multipoint lease line modem.

I have a network made up of these devices and need to source a replacement, hopefully without a complete overhaul.

I think I already know the answer and just need to hear it from others.

Please if anyone has any info let me know.

Thnks in advance.