How to cross lan cable and E1/T1/J1 cable

* E1 lines are specified for 120 ohm cables, so a CAT-5 or CAT-5e cable (100 ohm) is out-of-spec and thus not recommended for anything beyond lab use.

try Cables and Connectors for T1/E1 PRI Interface, ISDN PRI, Serial, WAN, IDSL