Motorola R2550 Service Manual

							6.
3. Turn  on  the receiver  (unsquelched). 
In-
crease  the receiver 
volume control to feed
audio  noise 
to the  R-2550 
Analyzer  (at
least  1/4 the  rated  audio  power). 
Record
the  noise 
reading  in 
dBm. Within 
the 
RF  Control  zone, 
adjust  the
RF  output  level 
until the noise  reading  is
less  than  20 
dB  from 
the value  recorded
in  step  3. Refer 
to your 
radios  service
manual  to determine  if 
any  adjustments
are  required.
NOTE:  To 
convert  the RF 
output  level to 
uV
or  dBV,  locate  the cursor  within the
Display  Control 
zone and 
press  the 
BF
DISPLAY  softkey. Locate 
the cursor  to
units  used 
for LvI: 
and select  the
required  unit 
using  the 
softkeys.
With  the cursor  within 
the RF
zone,  press 
the GEN  softkeY. Control
zone,  set the fi 
i r.l:irli:i: 
r.:ii:.ill:;i.lnTi:j
i::ii?J.;i::i:.    I:i;iri; 
i;f:l
Fttiti:  {j ii:.|;{ilii  Lli.i.r
Output  Level:  -115 
dB
lr.!:..ii  iii: l:,;  Fif 1.,1 j
lriir:ir:iiiii:.1ri|Ii.(r.  ijtr.iAdluslas
Required
5. Gensrator 
Mode
Soltkey
Within  the Audio  Control
modulation  off. 4-2.6 
Squelch  Sensitivity  Test
1. With  the 
cursor  located 
within the t{F
Control  zone, press 
the MON 
softkey.
Monitor  Mode
Softkey
i,Ji.rj:,..::: 
,ti: Tr:l:- 
flrriil i:::ii
Fixed  lkHz:  7 kHz 
x
{.1*jtti:  1 
i.l  :i.i:.r.]; 
iliiiii.iir  ii{,: !i
i:.ri+Fr;ti  rj 
l:rii 
iii:l  li
50 
						

							2. 
Disable  the 
PL/DPL  squelch if 
so
equipped.  Set 
the radios  squelch  control
to  the  point 
where  the 
receiver  barely
quiets.
3.  With  the 
cursor  located  within the 
RF
Control  zone, press 
the GEN 
softkey NOTE: 
To 
convert  the 
RF 
output  level 
to 
uV
or  dBV,  locate  the 
cursor  within the
Display  Contol 
zone and 
press 
the BF
DISPLAY  softkeY.
6.  Repeat  step 5 
with  the radios  squelch
level  set 
to maximum  tightness to 
deter-
mine  the tight  squelch  sensitivity  of 
the
radio.
7.  To 
check  PL/DPL  squelch sensitivity
locate  the 
cursor  within  the 
Audio  Con-
trol  zone 
and enter  the proper 
PL fre-
quency  or DPL  code 
Per APPendix 
B
lirir.li::i;itttr:  {|.(f.l 
i lk
li
						

							th 
the  cursor  located 
within the Audio
ntrol  zone, 
turn on  the modulation 
and
the  R-2550  synthesizer to provide 
a
ninal  750 Hz (500 
- I kHz) 
deviation
o  the  radios 
manufacturers 
specifica-
ts.
i.!3;..1iii;:.;;;;;  {!.i!tttrii.i
Fixed  lkHz: 
5 kHz 
_
Synth:  O.75 kHz 
-
!:i::t;ir,rl  i-l.i: 
lili..
i::+i1+  {fil
i.;ifi;-:t  (i.:.Jii 
kn;:l li
iliir:i$l  .{{:;l:iii:.Vili}iirjri.j{j:i.i
ble  the radios 
PL/DPL squelch cir-
Fully  open the 
carrier  squelch 
con-
hin  the RF 
Contol  zone, 
increase 
the
output  level until the  receiver  just
quelches.  This is 
the  coded 
squelch
iitivity.
li;: {.:{rtrlr:i!:  riii:.I,il:iflrf ili
frft?:till;    $,l.tl: 
l;}j
Fffi{i:  tjir:.ij{{:tiir,tiir
Output  Level:  -l 
12  dB
rJr.ii  iii: lr,: 
t1;: tii :
$ili:tii*iisr1fyi..{r.  ijiv:Adlusl 
as
R€qulred
52 
						

							A
AC
AM
ATTENAUTOBATTBNC
BWC
CAL CCIR
C&E Ampere
Alternating  Current
Amplitude  Modulation
Attenuation AutomaticBatteryCoaxial  RF 
Connector
Bandwidth CelsiusCalibrate
International  Radio
Consultative  Committee
Communications  and
Electronics  (Part 
of
Motorola) CentimetersComplementary  Metal
Oxide  Semiconductor
Counter Cathode  RaY 
Tube
Continuous  Wave
Decibel Decibel  (refened  to
carrier) Decibel  (referred  to
1  mW  into 
50 ohms)
Direct  Curent
Demodulation DeviationDispersion Distortion ApPendix 
A
LIST  OF 
ABBREYIATIONS
DivDPL
DTMFDurDVMEEA Division
Digital 
Private Line,
a  Motorola  registered
trademark Dual-tone multi-frequencY
Duration Digital  Voltmeter
Electronic Engineering Association
Electronics  IndustrY
Association
External
Frequency  Modulation
Frequency GenerateGigahertzHorizontal
Hertz Integrated  Circuit
Instantaneous Deviation
Control
Institute  of 
Electrical  and
Electronics  Engineers
Interme  diate FrequencY
Input/Output KilohmKilohertzLight-Emitting  Diode
cm
CMOS
CntrCRT CW
dBdBc
dBmDCDemod DEVDisp DIST EIA
Extl FMFREQ
GENGHzHorizHzIC
IDC
IEEEIFVO Kohm
kHz
LED
53 
						

							OF 
ABBREVIATIONS-CONTINUED
rble
rdwidth
)  memory
)rd gistered
us
lency Square
recification SEQ
SINAD
SPF
STD
SWSWP
Synth
TN
Trig
TX
UHFV
VAC
VDC
Vert
VRMS
w
WBXCVR
XX Sequence
Ratio  of (Signal 
+ Noise
+  Distortion)/(Noise
+  Distortion):
Special  Function
Standard
Switch
Sweep Synthesizer
Tone
Trigger
Transmitter
Ultra  High 
Frequency
Volts Volts  Alternating
Cunent
Volts  Direct 
Current
Vertical
Volts (root-mean-square)
Watts
Wide  Bandwidth
Transceiver (Select  Any Valid
Number)
54 
						

							APPendix 
B
TONE  AND 
CODE  SPECIFICATIONS
Table  B-1. Standard  DTMF 
Tones
;ffiisionsforencoding.anddecoding16differentkevs.Eachkeyis assisnedtworrequen:i:;.::^rj:r*::xtfiilrlnili.i;Jf;[ft  lgiliffi SlTo
asslgneo  lw(J 
tlvgueil: 
-- 
with 16 ditterent  coml
rirll  pft 
*:1qr:a[g:f,3fii,Yi,ih:;ili  s 
 
i  oi 
eac 
tr kev
STANDARD 
DTMF 
(Hz)
697 770
852941
1209 1336
14771633
LOW
Low LOW
LOW HIGHHIGH HIGHHIGH
Table B-2. 
DTMF  FrequencY  Coding*
HIGH  GROUP  TONE
LOW  GROUP  TONE
1
2 3
A
456
B
7I
9
c
o #
D
55 
						

							Table 
B-3. Privare-Line  (pL) 
Codes
FREAUENCY (Hz)
xz
wz XA
WA
XB
WB YZ
YA
YB zz
ZA
ZB
1Z
1A
1B
22
2A
28
32
3A
3B
42
4A
48
52
5A
5B 62
64
6B
7Z
7A
M1 82
M2
M3
M4 92
M5
M6
M7 67.0
69.3
71.9
74.4
77.0
79.7
82.5
85.4
88.5
91.5
94.8
97.0
100.0
103.5
107.2
1  10.9
114.8
118.8
123.0
127.3
131.8
136.5
141.3
146.2
151.4
156.7
162.2
167.9
173.8
179.9
186.2
192.8
203.5
206.5
210.7
218.1
225.7
229.1
233.6 241.8
250.3
56 
						

							Table 
B-4. DPL 
Standard  Codes
023 o25
026031032043 o47
051054
065 071072073114
115116 125131
132134 143
152155 156
162165
172 174
205 223226 243 244245251 261263
265271 306
311315331
343351 364
365 371
411 412
413
423
431 432 445
464
465 466503
506 516 532546 565606
612624 627
631
632654 662
664
703712723
731 732734743
5,7 
						

							Fc 
sF I-3uF 
p 
K-
APPendix  C
OF  CMOS NTEGRATBD CIRCUIT 
DEVICES
rit  devices  used
rnt  afe  of 
the
lltlJ,ilJ  *
MOS  lCs 
are
r  static  charges
rdling,  shiPPrng
re  assernblies  rn
levices  are 
Pro.v-ld-
3:iffi:i1: such  as 
are  en-
ns  system
,iffi;HJft
,Oota*  even in 
a 
sYD-
i:,iill;,lff  li,ill
while  servicing  a 
cir-
:  l.,^lrtttv  after 
rnov-
;;litGt  uu *o*tn-
li*n-ttonos  to 
a 
bare
l:::i;ilsurrace  rhis
ll;g*t*t* NOTE
Y#,##ffi#fr WARI{IFIG
when  y**1fffi!ri,,
Y::;:{:f  ^i,;,;.i^;.r;:;;,T;,
good  growno 
!rrri  increase
wist  straV wtiiiffi 
shock
the  danger  ol
  iZi-  ; t* 
ent  aItY  tou 
ching
ttiriuouo7e  sources
z  gfrJ*1i$i;#tli.-*
e  NorrnallY,  circuit 
*:qt:-iffJt
5  l-iu1  .ff,:ilIili,..r.  *
,lllllJllffiJslY#,Tl;- Ts:ff  i$yl*;:tfi#ili1ii*
to  insure  th{
this  Practice
4  Hi1:H$33tr#:nrffi*(silk  n]lc
ute  to 
static  builduP
59 
						

							5.
jlt lte.ctrically  powered 
test equip_
ment  should 
be
&ffiffi:,l:,1Tri:rti,i.i
connecdng  rhe 
le:t  prru.. 
lirii.rrr,
disconnect  the test  probe 
prior 
to
removing 
the ground 
lead.
If  a circuit 
module  is removed 
from
rhe  sysrem, 
ir is  desirable 
;or;;;;,,,
or  a conductive 
surfa., 
ir;;;;;
sheer  of aluminum 
foifl ,f,ii  l, .
::l*:rrd  to 
ground 
,r,roeijdOr
or  resistance-
WARNING
:!  the 
aluminum 
foil is 
con_
:::,:o  directty 
to 
sround,  be
caufious  of possible 
electri-_
1yl  tho_ck  from 
contauing
the  foit  at 
the 
same 
time as
other  electrical 
circuits. 7 
rIlTlilff#?  be 
sure 
the sordering
8.  Prior 
to connecting 
jumpers, 
replacing
1i_r1uit  componenr., 
rr rru;;,.
;T?,.r,::Jll  jl;F;;;;T:..,,*,
::T,i,  J,J, 
,T:_:1fli::flX:*
any  sraric 
buildup 
u, or*..iul;;
procedure  l. Sin
can  exist 
across  ce 
voltage 
differences
I.,o.TT.n.,;  ; jil,],iT, 
i* ;:-
used 
if it 
is 
neces
,rhe  cMddffi: 
ffi ,lJ::,..l#ns 
on
board  wiring.
6.
60