Incoming call transfer delay from an FXO to an extension

Incoming call transfer delay from an FXO to an extension

Good Morning.
My asterisk has an AEX410 card with 3 fxo + 1 fxs.
The fxo ports are thus connected:
1: direct to a pstn line
2: connected to an analog ext of an alcatel switchboard (to use this as an in / out line)
3: connected to an ext. Analogue of an alcatel switchboard (to use this as an in / out line)

I have configured 3 dahdi channels with 3 inbound rules so that the calls go to 3 ext. Asterisk

The next thing that happens is:

The calls coming from port 1 fxo are instantly transferred to the ext asterisk, but calls that enter port 2 and port 3 take 5-6 seconds to be transferred to the corresponding asterisk ext.

Can someone help me solve or explain why it happens?

Thank you