CAS Conditional Access System - check connection

CAS Conditional Access System - check connection

I'm trying to automate the updating of smart cards in CAS (Conditional
Access System). The information is passed in hexadecimal, the CAS manual
gives an example of code to check the connection.
I made using the linux terminal using the command nc.
nc 192.168.54.6 7000
After the connection I send the string in hexadecimal.
12 00 01 00 00 00 01 07 D9 0A 01 0C 1E 00 01 00 00
But in the CAS server says that the package is too large and that the
limit must be < 5000. I've tried changing the packet size by changing the
last two bytes, plus the error still remains. Then I'll post the error in
more detail.
Someone has worked with cas?