ARN max external clock rate

[kv123]

Hi,
Does anyone know answers on following questions?
1. What is max aggregate clock rate on ARN router?
2.What is max external clock rate on 3-serial module on ARN?
3.What is max external clock rate on 7-serial module on ARN?

I have 3-Serial Module in ARN router, and can I have COM1 with max speed
2Mbit/s and COM2 with max speed 2Mbit/s, that means max throughput 4Mbit/s
on ARN router?

I would appreciate any help.

Regards,
Ivana,