Section 150-232-100
Revision 01
Page 7
3.10 The reconstructed HDSL data channel is buffered in a first-in-first-out buffer (FIFO) within the multiplexer. A
frequency synthesizer in conjunction with the FIFO regulates the output bit rate and reconstructs the DS1 clock at
the exact rate received from the remote end. The HiGain system operates at DS1 rates of 1.544 Mbps with up to
±200 bps of offset.
3.11 A DSX-1 interface driver converts the DS1 channel to an AMI or B8ZS format, as determined by the T1 input
data to the HLU (when in AUTO mode) or by the user setting. The DSX-1 equalizer is programmable to five different
lengths as determined by the distance between the HLU and the DSX-1 interface. This provides CB-119 compliant
pulses at the DSX-1 interface over a range of 0-655 feet of ABAM cable. An external equlizer setting is also available
for use with external equilizer hardware.
3.12 The HLU-232 contains two separate power converters. The main power supply converts -48V local battery to
logic power for the HLU-232 circuits. The line power supply converts the -48V battery to a -130V dc (no doublers) to
-200V dc (doublers) feed that provides simplex power feed on the two HDSL line interfaces. The line power supply
can be turned on or off by the micro controller and is automatically shut down in the presence of line short circuits or
micro controller failure.
3.13 A female 9-pin RS-232 DB-9 connector is provided on the front panel of the HLU-232 (see Figure 4). This
connector provides asynchronous access to the HiGain system maintenance, provisioning and performance
monitoring firmware. The port is configured as DCE with 8 data bits, 1 stop bit and no parity. Operator interaction
with the firmware is via an ASCII terminal or a Personal Computer with asynchronous communication software.
Striking the SPACE bar several times enables the HLU-232 List 1D to automatically match the terminal line baud
rate, from 1200 to 9600 baud. Figure 7 through Figure 18 show the menu selections available from the terminal for
non-Doubler applications, and Figure 20 through Figure 42 show the menu selections available from the terminal for
Doubler applications. Table 12 defines the various terms used in the non-Doubler System Status Screen, and Table
24 defines the same terms for the Doubler System Status Screens.
