PN/DP CPU (get/put) and CP341-1 (Ag send & receive)

well, the issue here is that the functions used vary.

So if you use PN Interfaces by the CPU itself you may only use the T-Functions, provides as open communication in the FB 63 to FB 68.
As soon as you use CP’s in the S7-300 you always use FC 5 / FC 6 known as AG_SEND / AG_RECEIVE. If you have the latest CP’s in the S7-400 you may choose from the T-Functions or the AG_LSEND / AG_LRECV (FC 50 / FC 60) Functions depending on the way you want to configure the communication.

This is the main difference the AG_(L)SEND / AG_(L)RECV Functions are always configured in NetPro. There you preset the type of configuration, the destination and the Port / TSAP used.
If you use the T-Functions you do not use NetPro at all, there you only use the Open Communication Wizard and you configure your connections within a dataset which is placed into a DB which then is called in the PLC program.

At the end you use the same Protocols. So you surely may use an AG_SEND Connection with ISO on TCP on the CP and an ISO on TCP connection configured with the Open Communication Wizard and T-Functions on the other. The things to care about are the parameters used in both connections they have to be the same... vice versa.

I hope I could answer your question with this.

Best regards