# T1 and E1 Interface Options

Hold Time: Enter the number of milliseconds after an interface has transitioned from up to down (or down to up) before the interface is advertised to the system as being down (or up).

Clocking: Specifies the clock source.

Internal: Select this option to use the device's internal clock.

External: Select this option to use the DCE's clock.

Line buildout: (T1 only) Sets the cable length, in feet. Select a length from the scrolling list.

Line Encoding: (T1 only) Select Automatic Mark Inversion or 8-bits Zero Suppression.

Byte Encoding: (T1 only) Select 7-bits per byte or 8-bits per byte.

Frame Checksum: Select 16-bits or 32-bits.

Framing Mode: For T1 interfaces, select Super Frame or Extended Super Frame. For E1 interfaces, select with CRC4 for G704 mode with cyclic redundancy check 4 (CRC4), without CRC4 for G704 mode without CRC4, or Unframed for unframed transmission format.

Transmitting Flag in Idle Cycles: Select 0x7E to be transmitted in idle cycles, or select 0xFF to be transmitted in idle cycles.

Start/End Flags on Transmission: Select Filler to send two idle cycles between start/end flags, or Share to share start/end flags on transmit.

Invert data: Select this option to use data inversion.

Remote Loopback Respond: (T1 only) Select this option to have the interface respond to loop requests from the remote end.

Time Slots: For T1 interfaces, enter values from 1 to 24. For E1 interfaces, enter values from 2-32. Use hyphens to specify a range. Use commas (with no spaces before or after) to separate individual timeslots or ranges. For example, 1-3,5,22-24 are valid values for T1 interfaces and 2-5,9,22-32 are valid values for E1 interfaces.

Diagnosis Options: Sets the Bit Error Rate Testing (BERT) parameters.

BERT Algorithm: Select an algorithm from the scrolling list.

BERT Error Rate: Enter a value between 0-7, which corresponds to a bit error rate from 10-0 (1 error per bit) to 10-7.

BERT Test Length: Enter a value between 1-240 seconds.

Loopback Mode: Specify None, Local, Remote, or (for T1 only) Payload.