Installing the Unit
2-2
7914-A2-GB20-00
February 1998
Planning for Your SDSL Application
A pair of Hotwire 7914 Termination Units operates on a standard twisted-pair
phone line. Observe the following restrictions for a successful installation:
Be sure the line consists of twisted pair. Any flat cable has a major negative
effect on loop length that can be supported.
Use Category 5 cable for the user connections.
Plan the phone line to be dedicated to SDSL. The same phone line used for
the 7914 Termination Unit pair cannot also be used at the same time to carry
other voice or data services. This is because the SDSL frequency spectrum
overlaps with the voice band (including voice, fax and analog modems), as
well as the higher spectrums of digital services (including ADSL, HDSL or
ISDN).
Measure or estimate the length of the phone line you plan to use. Hotwire
7914 Termination Units support connections as distant as 18,000 feet (over
three miles) on noise-free 24 AWG wire.
The actual loop length that can be supported will vary, depending on:
— The loop cable gauge
— Noise introduced from neighboring phone lines in the same binder group
or cable (which can change over time)
— Noise introduced at either termination unit, such as interference from a
PC monitor if the phone line is too close by (which can change over time)
Although the line rate is 1.54 Mbps downstream and upstream
simultaneously, the actual throughput will vary depending on:
— Any interfering loop noise present in the cable
— Quality and wire gage of the connecting cable
Handle the termination unit with care and use it in the proper environment.
NOTE:
Keep the cover on the termination unit for performance and for safety
reasons.
