HP 4937A Service manual

HP
4937A

MODEL 4937A
SECTION I
GENERAL INFORMATION
1-1. INTRODUCTION
1-2. This Operating and Service Manual contains information required to install, operate, test, adjust,
and service the Hewlett-Packard Model 4937A Transmission Impairment Measuring Set, Figure 1-1
shows the instrument and accessories supplied. Throughout the remainder of this manual the Model
4937A wili be referred to as HP 4937A or the instrument.
1-3. The Manual part number is listed on the title page. Also listed on the title page of this manual is
a Microfiche part number. This number can be used to order 4X 6 inch microfilm transparencies of
the manual. Each microfiche contains up to 96 photo-duplicates of the manual pages. The microfiche
package also includes the latest Manual Changes supplement as well as pertinent Service Notes.
1-4. SPECIFICATIONS
1-5. Instrument specifications are listed in table 1-1. These specifications are the performance
standards or limits against which the instrument is tested. Supplemental characteristics are shown in
the shaded areas or in italics and are intended to provide information useful in the application of the
instrument. These specifications are not warranted performance parameters. Performance tests are
listed in Section IV of this manual.
1-6. SAFETY CONSIDERATIONS
1-7. This product is a Safety Class 1 instrument (provided with a protective earth terminai), The in¬
strument and manual should be reviewed for safety markings and instructions before operation.
1-8. INSTRUMENTS COVERED 8Y THIS MANUAL
1-9. Attached to the instrument is a serial number plate. The serial number is in the form:
OOOOAOOOOO. It is in two parts; the first four digits and the letter are the serial prefix and the last
five digits are the suffix. The prefix is the same for all identical instruments; it changes only when a
change is made to the instrument. The suffix however, is assigned sequentially and is different for
each instrument. The contents of this manual apply to the instruments with the serial number
prefix(s) listed under SERIAL NUMBERS on the title page.
1-10. An instrument manufactured after the printing of this manual may have a serial number prefix
that is not listed on the title page, This unlisted serial number prefix indicates the instrument is dif¬
ferent from those described in this manual. The manual for this newer number is accompanied by a
yellow Changes Sheet supplement. This supplement contains ^’change information” that explains how
to adapt the manual to the newer instrument.

^ 4937A
^AL INFORMATION
For information concerning a serial number prefix that is not listed on the title page or in the
I Changes supplernent, contact your nearest Hewlett-Packard sales office.
DESCRIPTION
The HP 4937A is a voice band Transmission impairment Measurement Set that also Incor-
3 S signaling capability. These features, combined with the instruments light weight, provides a
3 le field service tool for fast, accurate network access testing. The HP 4937A signaling feature
3 used to verify the proper installation of PBX systems.
The transmission impairment measurements that can be made using the HP 4937A are listed
ilow:
i. Level and Frequency
I Noise
I Noise with Tone
1. Signal to Noise
5. Noise to Ground
3. Return Loss
The procedures for using supervisory signaling, and for making the transmission impairment
urements, are described in Section lil of this manual.
Supervisory signaling is used to detect or change the state or condition of a subscriber or
ork line. There are two supervisory conditions; on-hook and off-hook. The on-hook condition
en the telephone is idle. That is the handset is resting on the cradle and the grounding switch is
- Off-hook condition is when the telephone is active. That is when the handset is removed from
radle and the grounding switch is closed.
.. These on-hook and off-hook conditions provide circuit indications such as circuit idle, circuit
, seizure, and disconnect,
}. The HP 4937A can perform the following supervisory signaling functions:
1. Loop start signaling
2. Ground start signaling
3. Loop reverse battery signaling
4. E/M signaling Types i, II, and lil
E
-1
•1
E
E
E/
i
Ei
■ TOE!
;NEI
- 1 1,
I
* Inua
: 12 .
- 1 3 .
.'^rat^
‘ irtat
an bi
•' -14,
b€
i
I
neas
1 6
ietw'
; wh
pen,
yr-\7
ie c
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■ i-ia
'|jsy
5
E"
E
E
5
5. Wink

MODEL 4937A
GENERAL INFORMATION
1-20. OPTIONS
The following options are available:
1, Option 001 adds a rechargeable battery pack.
2, Option 002 deletes 900 ohm and adds 1 SO ohm impedance,
3, Option 910 includes an additional Operating and Service Manual.
1-21. WARRANTY
Instrument warranty is as listed inside of the front cover.
1-22. ACCESSORIES AVAILABLE
1, Test Cord w/310 male to alligator clips, 60 inches, HP P/N 18182A
2, Test Cord w/310 male at both ends, 36 inches, HP P/N 15513A
3. Standard 19-inch rack mounting kit, HP P/N 18132A
4. Ladder bracket, HP P/N 18161A
1-23. RECOMMENDED TEST EQUIPMENT
1-24. Equipment required to maintain the Model 4937A Is iisted in table 1-2. Other equipment may be
substituted if it meets or exceeds the critical specifications listed in the table.
1-25. BATTERY OPERATION (Option 001)
1-26, instruments with Option 001 have nickel-cadmium batteries that enable the HP 4937A to
operate from internal power when in areas where ac power is not available. Typical operating time is
S hours when the batteries are fully charged. The batteries are trickle charged whenever the instru¬
ment is connected to an ac power source and the POWER switch is in the STBY position.
1-27, Regular discharge/charge cycles are recommended to maintain maximum battery capacity.
The instrument should be operated until the batteries are discharged (when LOW BATTERY indicator
is displayed in the left display) then recharged, at least every 30 days. Normal recharge time is
about 14 hours. Typical battery life under norma! operating conditions should be at least 100 char¬
ge/discharge cycles.
Note
Batteries do not charge when the HP 4937A is operating from an ac source.

. 4937A
\AL INFORMATION
Charging the Batteries
%
ODEl
= NEF
28.
The internal battery consists of one 15-volt rechargeable battery pack. To recharge the bat-
connect the HP 4937A to an ac power source and press the power switch to STBY (the bat-
wil! not charge with the power switch in the ON position). Normal recharge time is about 14
Charging Temperature
|29.
hes,
Ties
•^urs,
(
I
i
-30.
The batteries may be charged at temperatures between +5 degrees C and +40 degrees C (+41
3 S F and +104 degrees F), but wiil have greater charge capacity if charged between +5
3 s C and +25 degrees C (+41 degrees F and +77 degrees F). At temperatures above +25
5 S C the charge acceptance fails off as shown in figure 1-2, For example, a cell charged at
egrees C accepts about 60 to 70 percent of its rated capacity. Temperatures below +5
3 S C cause pressure to bulid up within the ce!! as it is charged, which couid result in venting of
il. This can result in permanent degradation of the battery capacity due to loss of electrolyte.
■ i
•31,
egref
-\gre«
^gre;
45 d
egret
e ce
. Operating Temperature
Normal operating temperature of the HP 4937A with batteries should be between 0 degrees C
40 degrees C (+32 degrees F and +104 degrees F). However, there will be a loss of capacity
operating at the extremes. At low temperatures, the batteries cannot fully discharge even
h they were fully charged at room temperature. At high temperatures the same effect takes
but to a lesser degree, in addition to charge acceptance previously mentioned. Figure 1-2 il-
tes this elfect.
CHARGING TIME IN HOURS - 0.1C CHARGE RATE
Figure 1-2. Charge Acceptance at Various Temperatures
i
i
32
-33.
nd +
hen
'lougi
iace,
stra
6-
5 :
E-
C'l ■ 1-4

MODEL 4937A
SPECIFICATIONS
Table Specifications
LEVEL/FREQUENCY
Transmitter
Frequency:
Range: 20 Hz to 9999 Hz
Resolution; 1 Hz
Accuracy: +/-0.005% of output frequency
Preprogrammed functions:
SF Skip; skips the frequency band from 2450-2750 Hz
Frequencies: at power up 404 Hz, 1004 Hz, 2804 Hz, and 2713 Hz
Level:
Range: -40 to +13 dBm
Resolution: 0.1 dB
Accuracy ((«) 1004 Hz, -19 dBm to 0 dBm), +/-0.1 dB; (elsewhere) +/-0.2 dB
Flatness (referenced to 1 kHz, in dB)
Frequency (Hz)
20 200 4000 3999
*13
Level
(dB) +10
-40
Distortion (in dB from fundamental)
Note: (Includes harmonics, spurious, and background noise within a 3 dB bandwidth of 4 kHz or 4
X f^whichever is greater.)
40
Level +13
(d8)
+ 10
0
-40
Note: At 1004 Hz, 0 dBm, threshold is more than 65 dB down when using a 4-kHz filter.
Frequency (Hz)
100 4000 9999
-20
- 45 - '
-45
-30
-55
: -55
■ -40
-50
-50
+. 5 ,- 3.0 +/- 0,.,2
+/- 0.2
+/- I . 0 '
1
o
+/- 0.2

;L 4937A
:lFICAT!ONS
Table Specif cations (con’t)
sceiver
equency:
inge: 20 Hz to 9999 Hz
(Solution: 1 Hz
xuracy: +/-1.0 Hz
vei:
.nge: -60 to +13 dBm
solution: 0,1 dB
curacy: (in dB)
Frequency (Hz)
20 50 200 4000 9999
/el +13
n
-40
-50
te: Receiver accuracy not specified below 500 Hz when using 150 ohm termination. (Instruments
with option 002.)
te: At 1004 Hz accuracy is rZ-O.! dB from -20 to +13 dBm.
OSS Talk: >78 dB isolation (a 4 kHz, decreasing 6 dB per octave above 4 kHz.
^programmed Functions:
nge Hold: Inhibits the autorange from changing from its present setting.
“SSAGE CIRCUIT NOISE
msmitter; quiet terminated
seiver:
nge: 0 to 99 dBm; 150 ohms, lower limit is 7 dB higher (Option 002 instruments only)
solution: 1 dB
ouracy: +/-1 dB from 10 to 99 dBm
+/-2 dB from 0 to 10 dBm
ighting Filters: C-message, and 3 kHz Flat

MODEL 4937A
SPEClFiCATlONS
able Specifications (con't)
NOISE WITH TONE
Transmitter;
Frequency: 1004 Hz fixed tone (for other specifications, see Transmitter
Frequency)
Receiver:
Notch Filter; >50 dB rejection from 995- to 1025-Hz
Weighting Filters: C-message, and 3 kHz flat
Range; lOto 39 dBm (600, 900, and 1200)
Resolution: 1 db
Accuracy: +/-1 dB from 20 to 99 dBm
+/-3 dB from 10 to 20 dBm
SIGNAL-TO-NOISE RATIO
T ransmitter:
Frequency: 1004 Hz fixed tone (for other specifications,see Level and Frequency)
Receiver:
Signal Level Range: -40 to +13 dBm
Ratio Range: 10 to 45 dB
Resolution; 1 dB
Accuracy: +/-1 dB
NOISE-TO-GROUND
Transmitter; quiet terminated
Receiver:
Weighting Filters; C-message, and 3 kHz flat
Range: 50 to 99 dBm (600, 900, and 1 200 ohms)
Resolution: 1 dB
Accuracy: +/-1.5 dB
RETURN LOSS
2“Wire: 600 and 900 ohms only (600 ohms Option 002)
Transmitter:
Level Range: -26 dBm to -2 dBm
Resolution: 0.1 dB
Transmitter Spectra:
Echo, singing return loss low, and singing return loss high spectra all meet the
specifications of IEEE standard P743 and Bell System Publication 41009.

CATIONS
Table Specifications (cont)
'URN LOSS 2-wire: (con't)
siver;
ge; 0 to 40 dB
oiution: 0,1 dB
•nal Hybrid Impedance;
ofarads (+/-1%)
600 ohms (+/-0,1%) or 900 ohms C+/-0,1%) in series with 2.16
//ire: 600 and 300 ohms only (600 ohms Option 002)
nsmitter:
el Range; -26 dBm to -2 dBm
oiution: 0.1 dB
o'sl“gm"reTur ' loss low, and smgmg return loss Wgh spectra all meet the
olfications of IEEE standard P743 and Bell System Publication 41009,
:eiver:
ige: 0 to SO dB
solution; 0.1 dB
auracy: +/-0,5 dB overall
anshybrld Loss Compensation;
-29.9 dB to +29.9 dB in 0.1 dB steps

model 4937A
SPECIFICATIONS
Table 1 - 1 . Specifications (con-t)
SUPEBVISORY SIGNALING
E/M Signaling
Types: Type l, !l. and 111 (both originate and
mA
Supervision Sensors Threshold Voltages:
terminate) Battery: -48 Vdo current limited to 29
Voltage;
Type I
Type II
Type III
E Lead
<-l6V = on hoo'K
>-l6V • off Viook
On-Hook Off-Hook
open
gnd
open
3G
open
gnd
:ype I
Dype II
Type II
M Lead
>_i_6V = on hook
<-15V = off hook
On-Hook Off-Hook
gnd
toatt
open
SB
3G
SB
Loop Signaling
Types: Loop Start, Ground Start, and Loop Reverse Battery (both originate and terminate)
Ba«e?r-48v'dc"wr340 oLl^:sir^^
Bridging Loss of Battery:
<0.5 dB from 200 Hz to 500 Hz
<0.3 dS from 500 Hz to 10 kHz
W!NK
Idle; 100 msec (nominal)
Off Hook: 200 msec (nominal)
status indication of on-HooL and off-HooK for both originate and terminate ends o, the
frunk, except Loop Start which only indicates originate .

EL 4937A
:iFICATIONS
Table Specifications (con't)
ENERAL
aximurn DC Blocking: 200 Volts
pedances: 600, 900, and 1200 ohms, aRIDGE. TRMT and RCV impedances independently
ilectable
idging Loss to 10 kHz: <0.2 dB
jcelver Return Loss: >30 dB from 50 Hz to 4 kHz at 600, 900, and 1 200 ohms
>30 dB from 800 Hz to 10 kHz at 150 ohms (option 002)
mgitudinal Balance: >80 dB at 60 Hz; >70 dB at 540 Hz; >60 dB up to 4 kHz decreasing 6
dB per octave to 10 kHz,
)wer Requirements: 100 V, 120 V, 220 V, and 240 Vac -r5%, -10%, 48-66 Hz
ittery Supply (option): Typically >5.0 hours of continuous operation at 25 C. Complete
recharging in 14 hours with unit in STBY.
imperature Range: 0 C to +55 C, (+32 F to +1 31 F); 0 C to+ 40 C with batteries (+32 F to
+ 110 F)
arm up time (p 20 C for stated accuracy: 5 minutes
mensions:279mmx 127 mm x381mm(5in, xllin, x15 in.)
eight: 5.3 kg (12 lbs)
7.6 kg (17 lbs) with batteries
Dtions
001: Adds rechargeable battery pack
002: Deletes 900-ohm impedance atid adds 150-ohm impedance
910; includes extra Operating and Service Manual
;ODE
PEC
G
Mi
!m
S€
Br
Ri
Lc
Pc
Be
T«
W
Dil
W
Of

Table 1-2. Recommended Test Equipment
Critical Recommended
.Instrument Specifications Model
Use
Ac Calibrator Output: imV to lOV Fluke 5200A P,T
Freq; 20Hz to 4 kHz
Accy; 0.02%
Ac Voltmeter 5 1/2 digit, 0,1% HP 3456A P,T
Multimeter
current
HP S'iSSA ?,T
Oscilloscope Dual Chan; 5mV/div HP 1740A ?,A
Signature
Analyzer
CMOS levels
Qualifer
HP 5005A I
Audio
Analyzer
20 Hz to 4 kHz
H? 3903A
F.A
Counter
10 kHz
HP 53 loA
Power Supply 50 volt
HP SOlfiR
Service bracks ;ts
HP P/N 1531- •0211
DIP
switch
HP P/N 1251-
■ 7158
Res istor, 398
ohm 1%
HP P/N 0698- -9100
Res
istor, 600 ohm 1%
HP P/N 0698-
-7408
Res istor,
900 ohm 1%
HP P/N
0698-
-6344
MODEL 4937A
SPECIFICATIONS
A=Adjustments
P=Performance Test
T=Trouble shooting

SECTION n
INSTALLATION
MODEL 4937A
INSTALLATION
2-1. INTRODUCTION
2-2. This section provides installation instructions for the Mode) 4937A TIMS, This section also in¬
cludes information about initial inspection and damage claims, preparation for use, power require¬
ments, storage and shipment.
2-3. INITIAL INSPECTION
2 - 4 . inspect the shipping container for damage, if the shipping container or cushioning material is
damaged, it should be kept until the contents of the shipment have been checked for completeness
and the instrument has been checked mechanically and eiectricaiiy. The contents of the shipment
should be as shown in figure 1-1. The procedures for checking eiectricai performance are given in
Section IV. If the contents are incompiete, if there is mechanical damage or defect, or if the instru¬
ment does not pass the performance tests, notify the nearest Hewlett-Packard sales and suppui t of¬
fice. If the shipping container is damaged, or the cushioning materia! shows signs of stress, notify the
carrier as well as the Hewlett-Packard sales and support office.
2-5. PREPARATION FOR USE
CAUTION
Before connecting this instrument to an ac power source, be sure
that the rear pane! line module is set to the same voltage as the ac
source and that the correct fuse for that ac voltage is instaiied.
2-6. Power R<=>nujrements
2 - 7 . This instrument requires a power source of 100-, 120-, 220-, or 240-Vac, +5% or-10%. Single
phase 48- to S 6 -H 2 ,
2-8, Option 001 instruments have a battery power supply. The battery pack provides up to 5 hours
of continuous operation at 25 degrees C. Complete recharging in 14 hours with unit in STBY mode.
2-9. Line Voltage Selection
2-10. Figure 2-1 provides instruction for line voltage and fuse selection. The line voltage selection
and fuse are factory set for 120 Vac operation.

4937A
llation
Figure 2-1. Line Voltage Selection
Power Cable
WARNING
Anv interruption of the protective (grounding) conductor
Side tt instr^e^^ or dieconnecting the protective earth terminai can
make this instrument dangerous to electrical shook.
<er cables.
!3. OPERATING ENVIRONMENT
4. Temperature
'"eITtf"l3Td"Igrs'rre"ureTrn^^^^^
3 degrees C (+32 degrees F to +104 degrees F).

Plug Type
I
Table 2“T Pou’c-?>' Cables Available
Cable
HP Part
Nu mber
8120-1351
8120-1703
8120-1369
8120-0696
8120-1689
8120-1692
8120-1348
8120-1398
8120-1754
8120-1378
8120-1521
8120-1676
8120-2104
8120-0698
Plug
Description
Straight *BS1 363A
90°
Straight *NZSS198/ASC11 2
90°
8120-1957
8120-2956
8120-1860
Straight 'CEE7-Y11
90°
Straight 'NEMA5-15P
90°
Straight *N£MA5-1 5P
Straight 'NEMA5-15P
90°
Straight *NEMA5-15P
Straight "SEVIO11
1959-24507
Type 1 2
Straight ' ■ NEMA6-15P
Straight *DHCK 107
90°
Straight ’CEE22-V1
(Systems Cabinet use)
MODEL 4937A
INSTALLATION
Cable
Cable For Use
Length
Color In Country
(inches)
90
Mint Gray United Kingdom,
90
Mint Gray Cyprus, Nigeria,
Singapore
Australia,
New Zealand
Mint Gray
Mint Gray
East and West
Europe, Saudi
Arabia, Egypt,
So. Africa, India
iunpolarized in
many nationsi
80
Black United States,
80
Black Canada,
36
Black Japan GOOV or
80
Jade Gray ZOOVi,
80
Jade Gray Mexico,
36
Jade Gray Philippines,
Taiwan
79
Gray Switzerland
United States
Canada
Denmark
___1-'--- ~ T u,-, .,n fnr rahie IS HP Part Number for complete cable
Part number shown for plug ,s industry identifier for piug only. Number shown

■ L 4937A
ALLATION
Humidity
This instrument may be operated in environments with humidity from 5 percent to 95 percent
ve humidil^at +40 degrees C ( + 104 degrees F), However, the instrument should be protected
temperature extremes that can cause condensation within the instrument.
3. STORAGE AND SHIPMENT
Environment
3, The instrument may be stored and shipped within the following environmental limits:
• Temperature. -20 to +65 degrees C (-4 to +149 degrees F)
• Humidity.Up to 90% Relative at +65 degrees C (+149 degrees F)
1. Packaging
2 Tagging for Service.—If the instrument is being returned to Hewlett- Packard for service^
se co^mplete one of the blue repair tags located at the back of this manual and attach it to the
•ument.
3 Original Packaging.—Containers and materials identical to those used in factory packaging are
■ iabie through Hewlett-Packard sales and support offices, if the instrument is being
/icina attach a tag indicating the type of service required, return address, model number, and full
al number. Also mark the container FRAGILE to ensure careful handling. In any correspondence,
ir to the instrument by model number and full serial number.
14. Other Packaglng,--The following general instructions should be used for repacking with com-
ically available materials:
Vrao the instrument in heavy paper or plastic, (If shipping to Hewlett- Packard office or semce
Inter, attach a tag indicating type of service required, return address, model number, and
umber.)
Use strong shipping container. A double-walled carton made of 350-pound test material is
dequate.
Jse a layer of shook -absorbing material 70- to 100-mm (3- to 4-lnohes) thick y ound all sides of
he instrument to provide firm cushioning and to prevent movement Inside the container, Protect the
ontro! panel with cardboard.
Seal the shipping container securely.
Vlark shipping container FRAGILE to ensure careful handling.
n any correspondence, refer to instrument by mode! number and full serial number.
^ • MST,
Zt ?
2-17
reiati
g 1 Tom
iii I 2-11
piea
insti
g, d.i

MODEL 4937A
SECTION III
OPERATION
3-1. INTRODUCTION
3-2 This section contains information on front and rear panel features, seif check procedures, and
error codes, It also describes typical operating modes. The principles of operation of the measure¬
ments are explained in Appendix A of this manual,
3“3. OPERATING CHARACTERISTICS
3-4 xhe HP 4937A provides two types of functions: Transmission Impairment Measurements and
Supervisory Signaling.
The transmission Impairment measurements that can be made with the HP 4937A are:
• Level and Frequency
• Noise
• Noise with Tone
• Signal to Noise
• Noise to Ground
• Return Loss
Signaling capabilities of the HP 4937A are:
• Supervisory signaling simulation
• Establishing talk condition for transmission testing
• Ability to hold two 2-wire circuits for testing
The types of supervisory signaling simulation are:
• Loop Start
• Ground Start
• Loop Reverse Battery
• E/M signaling Types I, II, and 111
• Wink
3-5. PANEL FEATURES
3-6. Figure 3-1 identifies the front and rear panel features and includes a brief description as to the
function of each feature.

del 4937A
:iOR MESG
7. SELF CHECK
c u b-c Thp<ip are a D0W6r on S6lt check and an ex-
S. The HP 4937A has two ° orocedure is performed automatically at power-up by
ded self check. The power on self che p should identify major problems. The error
instrument. !t checks ° V T:hTh7ests are m poTer and which are in ex-
ssage table listed below indicates externally jumper the E/M jack and the
,ded self check. To the SHIFT key and the FILTER select key. Failure of the instru-
;if1i^^as:ry*seTVhrk^"rcl^^lhl'^ a malfunction that cah possibly affect other
asurements,
9. ERROR MESSAGES
• 10. The HP 4937A gives two types
notional error in one of the self check
0 * error messages. The two types ot messages are either a
modes or an operational error. The errors are listed below.
-11. Operational Errors:
■ r 01-This error indicates that the receive level Is greater than the upper limit tor the selected
measurement,
-r 02 - lndioates that the receive level Is under the lower limit for the selected measurement,
j-c 07--This error signifies the loss of the 1004 Hz hold tone.
rr 09 -indicates that the level measurement currently being made needs to auto range and the
Range Hold mode is set,
:rr 10 -lndicates that 1 200 ohms impedance is selected in two wire return loss. Only 600 ohms and
900 ohms are available.
;rr 30-Wink Is illegal setup for Loop Start and Loop Reverse Battery Originate.
;rr 31-in Loop Originate the incomming battery has negative on the tip.
3-12, power On Self Check Errors.
=rr 11 —indicates that the power up self test failed the ROM checksum.
Err 12 — indicates that the power up self test failed the RAM check.
Err 13-The magnitude of the cai level for the voltage to frequency converter is out of range
Err l 4 --Power up seif check failed to measure a frequency of 1004 Hz.
Err 15 —Measurement of the hold tone frequency is not 1004 Hz,
Err 1 6 —Power up self check failed to measure a proper level of +13.0 dBm,
Err 17-Level measured through the C-message filter Is not the proper amplitude.
3-2

MODEL 4937A
ERROR MESG
18 --Level measured through the 3-kHz flat filter is not the proper amplitude.
Err iQ-Leve! measured through the 60-Hz reject filter is not the proper amplitude.
Err 20--Levei measured through the QRMS detector is not the proper amplitude,,
Err 21—Level measured through the Return Loss detector is not the proper amplitude,
3-13. Extended Self Check Errors:
Err 50--Leve( of the Echo return loss waveform is not the proper amplitude,
5i--Level of the Singing High return loss waveform Is not the proper amplitude.
Err 52“~Level of the Singing Lo return loss waveform is not the proper amplitude.
53--The measured depth of the notch filter is too small. This test wiil tail if the level is too low.
The transmit level must be greater than -40 dBm to pass this test,
54_-The TIPPOS detector did not pass the test to detect the presense of 48 volt supply,
gj-j. 55~-The TIPPOS detector did not pass the test to detect the absence of the 43 volt supply,
5Q--jhe TIPNEG detector did not pass the test to detect the presense of 48 volt supply,
57 „ - jhe TIPNEG detector did not pass the test to detect the absence of the 48 volt supply.
58—The GNDCUR detector did not pass the test to detect the presense of current from the 48
volt supply.
Err 59-The GNDCUR detector did not pass the test to detect the absence of current from the 48
volt supply.
Err 60-The TERMCUR detector did not pass the test to detect the presense of current from the 48
volt supply.
£rr 61-“The TERMCUR detector did not pass the tost to detect the absence of current from the 48
volt supply,
Err 62--The E lead detector did not sense the presence of the M lead. The E/M jack must be con¬
nected to the SB/SG jack to pass this test,
Err 63—The E lead detector did not sense the absence of the M lead, The E/M jack must be connec¬
ted to the SB/SG jack to pass this test.
64—The M lead detector did not sense the presence of the E lead. The E/M jack must be con¬
nected to the SB/SG jack to pass this test.
Err 65—The M lead detector did not sense the absence of the E lead. The E/M jack must be connec¬
ted to the SB/SG jack to pass this test.
3-3