Yes a special E1 crossover cable is required if you are connection two Eclipses frames together back to back via the E-QUE card
The E-QUE interface can be used for both direct E1 to E1 port connections or to provide linking via trunk lines When the card is configured (in ECS / EHX) for E-QUE tielines or trunking then the card provides 2x E1 connections Each E1 connection provides 30 channels of G.722  or G.711 encoded audio, giving 60 channels per cardThese E1 connections are available on the rear card via RJ45 port #  1 and RJ45 port # 5, .
The E1 specifications are:
• HDB3 Encoding.
• Long Haul Receive Signal Level.
• E1 120 Ohm Transmit Pulse Amplitude.
• Balanced.
• 120 Ohm Line Impedance.
• No Signaling.
• G.722 or G.711 64 kbit/s Audio Encoding.
• Tx Clock locally generated.
• Rx Clock Line Recovered.
When trunking directly between two Eclipse frames using E-QUE cards the user will need to construct a crossover cable that is unique for this application only.  It only uses certain pairs of the CAT-5/6 cable as shown in the chart below: 
E1 Crossover pin out table








The diagram below shows E1 trunking using a direct connection between two matrices using a E1  CAT5 crossover
cable. The E-QUE interface should be set to E1 Direct / trunklines in ECS or EHX hardware setup.