Tellabs 263DC Manual

7te11abs
technical manual
76-81263DC
rev A
practice section 81263DC-1 /81263DC-2/81263DC-3
©Tellabs, Inc., 1 May 1984
all rights reserved, printed in USA
263DC Data Station Termination Systems
-
figure
1.
2630C-1
OST
Sysfem
page 1
page 2
page 5
page 10
page 12
page 11
page 13
contents
section 1 general description
section
2
application
section 3 installation
section 4 circuit description
section 5 block diagram
section 6 specifications
section 7 testing and troubleshooting
1. general description
1.01 The Tellabs 263DC-1 (figure 1), 263DC-2,
and 263DC-3 Data Station Termination (DS1)
Systems interface either a 2wire or a 4wire data
set with a 4wire transmission facility. All three
systems are compact, self-contained units that
provide data interface and power rectification/
regulation circuitry in an attractive enclosure that
can be wall mounted or placed on a desktop.
Power for these systems can be provided from
battery feed or sealing current derived from the
units' simplex leads, or from an external source of
either nominal 26Vac or -22 to -56Vdc. All three
systems feature prescription gain and loss in the
receive channel, prescription loss in the transmit the 263DC-2 and 263DC-3, this is in addition to
channel, and manual or two-tone loopback In any provided by the receive equalizer) for long
addition, both the 263DC-2 and 263DC-3 provide sections of nonloaded cable. The facility-side trans-
prescription active equalization in the receive formers can also be optioned to derive normal
channel. All three units also include a 20mA simplex leads, to provide an internal source of
sealing current source to provide sealing current sealing current to the facility, or to provide a return
for the 4wire facility. path for sealing current applied at the far end of
Note: Throughout the rest of this practice, the term the facility. (The 263DC must be powered from an
2630C refers to all three OST systems unless external source when the sealing-current source
otherwise indicated. option is selected.)
1.02 In the event that this practice section is re- 1.05 On the station side, the 263DC can be
issued, the reason for reissue will be stated in this optioned to interface either a 2wire or a 4wire
paragraph. modem. In either mode, the station-side port(s) pro-
1.03 The 263DC provides from -24 to +24dB of vides capacitively-coupled, balanced, 600-ohm
gain in the receive channel and from 0 to 24dB of terminating impedance.
loss in the transmit channel. Transmission levels in 1.06 The 263DC provides loopback of the facility
both channels are prescription-set in 0.1dB incre- for testing and troubleshooting. The loopback func-
ments via DIP switches. The maximum input and tion can be activated either remotely by transmis-
output level of each channel is +5dBm. While the sion of a 2713Hz tone or locally via a local loop-
263DC-1 provides no amplitude equalization, the back lead. When activated remotely, the 263DC
263DC-2 and 263DC-3 both contain active pre- can be optioned to restore normal operation upon
scription equalizers in their receive paths. The receipt of a second loopback tone or automatically
263DC-2's equalizer is slope-type, providing up to at the end of a 20-minute timeout period (receipt of
7.5dB of gain at 2804Hz (re 1004Hz) in switch- a second tone before the expiration of this timeout
selectable 0.5dB increments. The 263DC-3's equal- period will also restore normal operation). The
izer is a slope/bump-type equivalent to the Western 263DC system provides equal-level loopback with
Electric modei 309B. switch-selectable gain of 8 or 16dB in the loop-
1.04 Transformers· at both facility-side ports back path.
(receive output and transmit input) can be switch 1.07 Other standard features of the 263DC
optioned for balanced 1200-, 600-, or 150-ohm System include two 310-type test jacks and five
terminating impedance. The 150-ohm option pro- status-Indicating LEDs. The test jacks are opening-
vides approximately 2dB of slope equalization (for type and face the DST system at the receive output
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