E1/T1 - WAN line protocol

Just note:

WAN protocol has Voice CAS, MFC/R2, PIR, ATM, Frame Relay, X.25, HDLC, PPP, SS7, Transparent bit-stream, BSC. Next protocol’s layer have IP/IPX over Frame Relay/ PPP/ HDLC/ X.25, X.25 over Frame Relay (Annex G), BSC over X.25 (DMT and TCOP), SNA over X.25, PPPoE, PPPoA, IP over ATM.

E1/T1/J1 signal status

• ALOSV: Loss of Signal alarm
• LOS: Receive Loss of Signal
• ALTLOS: Alternate loss of Signal Status
• OOF: Out of Frame
• RED: Telco Red Alarm condition
• AIS: Alarm Indication Signal
• OOSMFV: Loss of Signaling Multiframe
• OOCMFV: Loss of CRC Multiframe
• OOOFV: Out of Off-Line Frame
• RAIV: Receive Loss of Signal
• YEL: Receive Telco Yellow Alarm

RJ 45 E1/T1 Pinouts
port A
1: RTIP 2: RRING 4: TTIP 5: TRING
port B
3: RTIP 6: RRING 7: TTIP 8: TRING

To cross cable or back to back cable, you can do it by swap between RTIP, RRING and TTIP, TRING check E1/T1 cross cable and How to cross lan cable and E1/T1/J1 cable or ss7box user guide (tapping line).