ACCURATE ELECTRONICS 104445A, Manual, Page: 3 / 6

ACCURATE ELECTRONICS INC Practice Section 104445A Rev B January 2014
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attenuator switches are set to -7dB,
the gain range of the splitter in
ports is +3 to –17dB. The splitter
attenuator switches, then, should be
set based on the incoming signal
level at the splitter in port and on
the input level(s) required by the
modems connected to the multiple
ports. Select the splitter attenuator
switch setting that places the
midpoint of the 20dB gain range at
each of the splitter out ports nearest
the input level required by the
modems. This same principle
applies to the combiner attenuator
switch setting (S1-3 and S1-4),
except that this setting is based on
the OUTPUT level of the modems
and the level required at the
combiner out port. Splitter and
combiner switch settings are listed
in Table 3.
4.07 To adjust the levels at the
splitter output ports, first set S2-3 and S2-4 as described in paragraph 4.06
and then request that 1004hz test tone be sent from the distant end at the level
specified on the CLR. With a 600-ohm terminated voltmeter connected to
the split out 1 jack, adjust the split out level 1 control to the level required by
the modem connected to port 1. Repeat this procedure for the remaining split
out ports.
4.08 To adjust the levels in the combiner channel, first set S1-3 and S1-4 as
described in paragraph 4.06. Then connect a voltmeter, terminated at the
impedance of the comb out port, to the comb out jack. Next, insert 1004Hz
test tone, at the transmit level of the modem, into the comb in 1 jack. Finally
adjust the comb in level 1 control to the level specified on the CLR. Repeat
this procedure for the remaining comb in ports.
5. CIRCUIT DESCRIPTION
5.01 See Figure 1.
5.02 This circuit description is intended to familiarize you with the 104445A
Dual 5-Way Balanced Active Data Bridge for engineering and application
purposes only. Attempts to troubleshoot the 104445A are not recommended
and may void your warranty. Troubleshooting procedures should be limited
to those described in Section 7 of this Practice. Please refer to Figure 1 as an
aid in following the circuit description.
5.03 The combiner channel of the 104445A consists of four (4) transformer-
coupled input ports and four (4) variable-gain operational amplifiers. The
output of each of the four (4) op-amps is combined in a summing amplifier
along with the bus extension input signal. The summing amplifier, which can
be set to one of three (3) switch-selected gain ranges, applies its output to the
power amplifier, impedance option switches, and finally to the balanced
output transformer. Both input and output transformers provide balanced
terminations, and their center taps, simplex leads.
5.04 The splitter channel includes a center-tapped balance transformer,
switch-selectable impedance option, and a distribution amplifier whose gain
range can be switch-set at any of three (3) levels. the output of the
distribution amplifier is applied to four (4) variable-gain op-amps, which
drive the splitter out-out ports, and to one fixed-gain buffer amplifier that
drives the bus extension output line. The four (4) variable-gain amplifiers
each apply their signals to the splitter output ports through individual power
amplifiers and center-tapped balance transformers.
5.05 An integral regulated power supply permits operation with an external
input between –22 and –56VDC. Reverse-battery protection is provided by
a blocking diode, while a high-voltage zener diode protects against transients
on the input line.
6. MECHANICAL OUTLINE
6.01 See Figure 2.
7. TESTING AND TROUBLESHOOTING
7.01 The Testing Guide Checklist (see Table 4.) may be used to assist in the
installation, testing or troubleshooting of the product. The checklist is
intended as an aid in the localization of trouble to a specific product. If a
product is suspected of being defective, a new one should be substituted and
the test conducted again. If the substitute product operates correctly, the
original product should be considered defective and returned to Accurate for
repair or replacement as directed below. We strongly recommend that no
TABLE 1 . External Connections.
PORT 1 COMBINER INPUT TIP 31
PORT 1 COMBINER INPUT RING 29
PORT 1 COMBINER INPUT SX (Simplex) 56
PORT 1 SPLITTER OUTPUT TIP 21
PORT 1 SPLITTER OUTPUT RING 25
PORT 1 SPLITTER OUTPUT SX (Simplex) 22
PORT 2 COMBINER INPUT TIP 37
PORT 2 COMBINER INPUT RING 55
PORT 2 COMBINER INPUT SX (Simplex) 54
PORT 2 SPLITTER OUTPUT TIP 19
PORT 2 SPLITTER OUTPUT RING 23
PORT 2 SPLITTER OUTPUT SX (Simplex) 20
PORT 3 COMBINER INPUT TIP 39
PORT 3 COMBINER INPUT RING 53
PORT 3 COMBINER INPUT SX (Simplex) 52
PORT 3 SPLITTER OUTPUT TIP 15
PORT 3 SPLITTER OUTPUT RING 1
PORT 3 SPLITTER OUTPUT SX (Simplex) 16
PORT 4 COMBINER INPUT TIP 49
PORT 4 COMBINER INPUT RING 51
PORT 4 COMBINER INPUT SX (Simplex) 50
PORT 4 SPLITTER OUTPUT TIP 5
PORT 4 SPLITTER OUTPUT RING 3
PORT 4 SPLITTER OUTPUT SX (Simplex) 4
BUS EXTENTION INPUT TIP 28
BUS EXTENTION INPUT RING 26
BUS EXTENTION OUTPUT TIP 8
BUS EXTENTION OUTPUT RING 10
COMMON SPLITTER INPUT TIP 7
COMMON SPLITTER INPUT RING 13
COMMON SPLITTER INPUT SX (Simplex) 9 or 11
COMMON COMBINER OUTPUT TIP 41
COMMON COMBINER OUTPUT RING 47
COMMON COMBINER SPLITTER OUTPUT SX(Simplex) 43 or 45
-BATT (-22 TO -56 VDC Filtered Input) 35
GND (ground) 17
FIGURE 3 . S1, S2 Locations.