Assuming the KX-TDA600 support T1 connection you can connect it to Asterisk using a T1 cards,
I was checking the product specification and it seems it does
• ISDN Primary Rate Interface (PRI) with QSIG and T1
Assuming the KX-TDA600 support T1 connection you can connect it to Asterisk using a T1 cards,
I was checking the product specification and it seems it does
• ISDN Primary Rate Interface (PRI) with QSIG and T1