Toshiba Strata Xii, Strata Xx General Description Manual

							a) External Page--the relay is activated when- 
ever the external page circuit is accessed. 
A “make” contact is provided for control 
of background music on external page. 
This is- required only when an external 
page amplifier is used. 
b) Night Relay Service-relay will provide a 
dry contact at the NR terminals on the 
front of the MPRU PCB. A strap option on 
the MPRU allows the NR relay to function 
in one of two modes: 
1) Answering Machine Control- if the 
strap remains intact, the relay is oper- 
ated continuously when the system is 
in night service. This mode is intended 
for indirect control of an answering 
machine. 
2) Night Bell Control -if the strap is cut, 
the relay pulses at a 1-sec. on, 3-sec. off 
rate whenever the system is in night 
transfer mode and an incoming call is 
ringing the system. This mode is in- 
tended to be used for indirect control 
of an external night bell. 
Station Message Detail Recording (SMDR): 
Adding the optional MSMU PCB allows data to 
be collected for each outgoing and incoming 
CO line call. This data may be output to a GENERAL DESCRIPTION 
‘, 
SECTION 100-020-100 
JUNE 1983 
printer or recording device- via the RS232C 
interface located on the MSMU. 
System Battery Back-up: 
’ An optional PCB can be installed in theSTRATA 
power supply to provide automatic switching to 
standby battery power. During *normal power 
conditions the batteries are kept fully charged 
by the power supply. 
5 
lo-key EKT: 
The IO-key E KT may be assigned to any station 
except #17. This EKT has full access to seven 
CO/PBX lines and can receive transferred calls 
on other lines. 
lo-key BLF EKT: 
The optional lo-key B LF EKT may be used 
at up to 15 positions (stations 10 through 25, 
except #17, only). The BLF will display the 
status of stations 10 through 25. 
Wall Mounting Kit for EKT: 
The STRATA EKT is easily converted for wall 
mounting with an optional handset hanger kit. 
Wall Mounting Kit for MKSU: 
The MKSU is shipped configured for table 
mounting, but the use of the optional wall 
mount bracket and a simple reversal of the back 
panel quickly converts it for wail mounting. 
-19-  
						

							TOSHIBA SYSTEM PRACTICES 
ELECTRONIC KEY TELEPHONE SYSTEM INSTALLATION 
SECTION 100-020-200 
JUNE 1983 
SGrata +’ - 
XII&xx 
INSTALLATION  
						

							TOSHIBA SYSTEM PRACTICES INS IALLAI IUN 
ELECTRONIC KEY TELEPHONE SYSTEM 
INSTALLATlbN 
SECTION 100-020-200 
JUNE 1983 
PARAGRAPH 
TABLE OF CONTENTS 
SUBJECT PAGE 
TABLEofCONTENTS 
................................................... ..i 
ILLUSTRATION LIST ii .................................................... 
GENERAL ...................................................................................................................... 
PACKING.. ; 
MKSU LOCATION REQUIREMENTS 
.......................................... 2 
Power Requirements ................................................... 
Ventilation Requirements. ............................................... z 
Environmental Factors. 2 . 
; 
........................................ . ....... 
Cabling Considerations. ................................................. 
MKSU MOUNTING................................................._ 
.... 
$ 
Table Mounting the MKSU ............................................... 
Wall Mounting the MKSU ................................................ z 
PRINTED CIRCUIT BOARDS. .............................................. 5 
MPRUPCBOptions 
POWER CONNECTIONS ...................................................................................................... 7” 
MPRU PCB installation 
................................................. 7 
PowerConnection................................; 
.................... 7 
PCBINSTALLATION .................................................... 8 
Memory Protection 
.................................................... 8 
TABLEA-CRDUPOSITIONS 
.............................................. 9 
PCB installation Sequence. ............................................... 
10 
TABLEB-MXPUPOSITIONS .............................................. 12 
MSMU Installation. 
.................................................... 12 
MOPU Installation. .................................................... 13 
CABLECONNECTIONS .................................................. 13 
System Cable Configuration 
......................................... 
4 .... _I3 
15 
Main Distribution Frame Configuration. ...................................... 
Station Cable Connections ............................................... 
15 
TABLE C-CROSS-CONNECT DATA (STRATA Xl I & XX). .......................... 17 
Intercom Code Assignment. .............................................. 18 
TABLE D-CROSS-CONNECT DATA (STRATA XX). .............................. 18 
CO Line Connection ................................................... 18 
DSS/BLF Connection. 
.................................................. 19 
OPX/Conventional Telephone Connection ..................................... 20 
Off Premise Line (OPL) Connection ......................................... 22 
Station Message Detail Recording (SMDR) Connection. ............................ 22 
ELECTRONIC KEY TELEPHONE INFORMATION. ............................... 23 
General ............................................................ 23 
EKTWallMounting .................................................... 24 
ConvertingtheEKT .................................................... 25 
EKTConnections ..................................................... 25 
SYSTEM POWER-UP INITIALIZE. 
........................................... 25 
Clearing Automatic Dialing. .............................................. 26 
SMDR Real Time Clock Adjustment. ........................................ 27 
Program Listing. ...................................................... 28 
SYSTEMTESTPROCEDURES 
.............................................. 28 
EKT Functional Check. 
................................................. 28 
OPX/Conventional Telephone Functional Check. ................................ 30 
OPL Circuit Functional Check. ............................................ 30 
SMDR Feature Functional Check. .......................................... 31 
Feature Check ....................................................... 32 
MISCELLANEOUS EQUIPMENT CONNECTIONS. ................................ 32 
Wiring Connections .................................................... 
32 
Music-on-hold/Background Music Source. ..................................... 32 
Music-on-hold Volume Control ............................................ 32 
External Paging Connections. ............................................. 32 
Direct External Speaker Connection. ........................................ 32 
External Amplifier Connection. ............................................ 33 
Talkback Amplifier. ................................................... 33 
Background Music. .................................................... 33 
Volume Setting Sequence. ............................................... 33 
Night Relay Service. ................................................... 33 
.- 
-_ 
_i- 
01 
02 
03 
03.00 
03.10 
03.20 
03.30 
04 
04.10 
04.20 
05 
05.10 
06 
06.00 
06.10 
07 
07.00 
07.10 
07.20 
07.30 
08 
08.00 
08.10 
08.20 
08.30 
08.40 
08.50 
08.60 
08.70 
08.80 
09 
09.00 
09.10 
09.20 
09.30 
IO 
10.10 
10.20 
10.30 
11 
11.00 
11.10 
11.20 
17.30 
II.40 
12 
12.00 
12.10 
12.20 
12.30 
12.40 
12.50 
12.60 
12.70 
12.80 
12.90  
						

							TOSHIBA SYSTEM PRACTICES 
ELECTRONIC KEY TELEPHONE SYSTEM 
INSTALLATlON 
ILLUSTRATION LIST 
FIGURE SUBJECT 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
25 
26 
27 
28 
29 
30 
31 
32 
33 
34 
35 
36 
37 
38 
39 
40 
41 
42 
43 
44 
45 
46 
47 
IN3 IHLLAI IUN 
SECTION 100-020-200 
JUNE 1983 
PAGE 
CRDUBATTERYSTRAP.. 
........................................ .._ 
... 1 
AMMUBArrERYSTRAP 
............................................... 1 
MSMUBATTERYSTRAP 
............................................... 2 
MKSU WALL MOUNTING KIT TEMPLATE. 
.............................. . .... 
3 
ASSEMBLED MKSU WALL MOUNTING KIT .................................. 
3 
MKSU.........................................................., 
.. 4 
MKSU 
MKSU 
.......................................................................................................................... ; 
MPRURELAYSOCKETS&SWITCH 
........................................ 6 
RELAYlNSTALLEDWlTHSW2SWlTCH 
.................................... 7 
POWER SUPPLY-TO-MKSU WIRING. 
....................................... 7 
AMMUONTOMCAU .................................................. 9 
CRDUONMCBU.................................................~ 
... 9 
CRDUONMDSU 
..................................................... 9 
PCBs IN MKSU (STRATA XII) ............................................ 
10 
PCBs IN MKSU (STRATA XX) 
............................................ 11 
MSMUCONNECTIONSTRAPS 
............................................ 12 
MSMU/RS232CCONNECTOR 
............................................ 13 
MOPUCONNECTIONSTRAPS 
............................................ 13 
SYSTEMDIAGRAM 
................................................... 14 
MKSU CABLE CLAMPING. 
............................................... 
-15 
MKSUCABLEROUTING ............................................... 15 
MDF/EKTWlRING 
.................................................... 16 
RJ25CWlRlNG 
...................................................... 19 
MKSUTOPCOVERREMOVAL 
........................................... 19 
MKSUUPPERCABLEROUTING 
.......................................... 19 
MDSUWIRING ...................................................... 20 
MOPUWIRING ...................................................... 21 
MPLUWIRING 
....................................................... 22 
MSMU-TO-PRINTER CABLING 
........................................... 23 
20-key EKT 
......................................................... 23 
lo-keyEKT 
......................................................... 24 
REMOVING EKTBASE 
................................................. 24 
EKTWIREACCESS 
................................................... 24 
EKT WIRE ROUTING. 
................................................. 25 
HANDSETHANGER KIT.. ............................................. 25 
AMMUBATTERYSTRAP 
............................................... 25 
SYSTEM INITIALIZING (STRATA XII). 
..................................... 26 
SYSTEM INITIALIZING (STRATA XX). ..................................... 26 
MSMU FACEPLATE 
................................................... 28 
SMDR PRINTOUT EXAMPLE (OUTGOING CALL RECORD). 
....................... 31 
SMDR PRINTOUT EXAMPLE (INCOMING CALL RECORD) 
....................... 31 
MPRU CONNECTION STRIP ............................................. 32 
IMPEDANCE SWITCH ON MPRU .......................................... 32 
EXTERNAL AMPLIFIER HOOK-UP ........................................ 33 
VOLUME SETTING CONTROLS ........................................... 34 
NRCONTACTS 
...................................................... 35  
						

							INSTALLATION 
SECTION 100-020-200 
JUNE 1983 
01 GENERAL 
01.01 This section describes the installation 
precedures necessary to ensure proper operation 
of the STRATA XII & XX systems. The instal- 
lation procedures for the two systems vary only 
in relation to size; all other factors are the same. 
02 PACKING 
02.01 When a STRATA system is received, 
examine all packages and carefully 
note any visible 
damage. If any damage is found, bring it to the 
attention of the delivery carrier and make the 
proper claims. 
02.02 Check the number of cartons and 
the contents of the STRATA shipment against 
the purchase order and packing slip. If it is de- 
termined that any cartons are missing, contact 
your delivery carrier immediately. If it is de- 
termined that any equipment within a carton 
is missing, contact your Toshiba supplier im- 
mediately. 
02.03 After unpacking (prior to beginning 
the installation), inspect all equipment 
for damage. 
If any damage is detected, contact your delivery 
carrier immediately. If possible, retain all the 
original packing material. 
CAUTION: 
When handling (ins taking, removing, examin- 
ing, etc.) a printed circuit board, do not touch 
the back (soldered) side or the edge connec- 
tor. Always hold a PCB by its edge. 
02.04 When packing or storing a CRDU, 
AMMU, or MSMU, ensure the following: 
Do not use plastic or any type of conductive 
material for packing either a CRDU, AMMU, 
or MSMU. Use plain paper. 
CAUTION: 
Conductive packing material may cause the 
internal back-up battery to discharge and 
damage the PCB. 
02.05 Whenever storing or shipping a CRDU, 
AMMU or MSMU always ensure that the battery 
strap is in the OFF position. See Figure 1 for 
the CRDU, Figure 2 for the AMMU, Figure 3 
for the MSMU. 
FIGURE l-CRDU BATTERY STRAP 
FIGURE 2-AMMU BATTERY STRAP 
NOTE: 
Always make sure the battery strap on 
the AMMU is in the ‘ON” position just 
prior to installation. If not, the SET LED on 
the 
MCA U will not operate. 
Also, if 
equipped, ensure that the battery straps on 
the CRDUls) and MSMlJ are in the “‘ON” 
position. 
-l-  
						

							INSTALLATION 
SECTION 100-020-200 
JUNE 1983 
FIGURE 3-MSMU BATTERY STRAP 
03 MKSU LOCATION REQUIREMENTS 
03.00 Power Requirements 
03.01 
The STRATA MKSU (both XII & XX) 
requires 24 VDC. This is provided by the power 
supply (EPSA), which in turn requires power 
from a grounded 115 VAC outlet. The outlet 
should be separately fused and rated at 15 amps. 
03.02 
The same EPSA power supply is used 
with both STRATA systems. 
03.03 The 54-inch cord provided to connect 
the EPSA to the MKSU dictates the relative 
location of the power supply. The power supply 
is also equipped with a lo-ft. AC power cord. 
03.04 
An optional battery back-up unit 
(PBBU) is available for the power supply. It is 
a printed circuit board that mounts inside the 
power supply housing. The recommended bat- 
tery pack, which is customer-supplied, consists 
of two maintenance-free automobile 12 VDC 
batteries (maximum 80-amp/hr rating). With 
the optional PBBU assembly installed, all func- 
tions of either STRATA system will continue 
to operate for several hours after a loss of normal 
electrical power (the actual period of time is in 
direct ratio to the type and size of batteries se- 
lected). No calls will be disconnected during 
switch-over to battery power. 03.10 
Ventilation Requirements 
03.11 
Sufficient ventilation should exist to 
_ 
allow dissipation of the heat generated by the 
power supply and MKSU. 
, 
03.20 
Environmental Factors 
03.21 Humidity at the MKSU location 
should be within 20~80% (without conden- 
sation), and the temperature should be rela- 
tively constant within a range of 32~122’F 
(0 w 5o’C). Exposure 
to dust and airborne 
chemicals should also be taken into consider- 
ation. 
03.30 
Cabling Considerations 
03.31 
The MKSU must be located so that 
all stations are within 1000 cable feet (305 m) 
of it. The DSS console must be located within 
500 cable feet (152.5 m) of the MKSU. Accept- 
able cable is 22 or 24 AWG inside telephone 
station cable, jacketed but not shielded, having two 
or more twisted wire pairs. 
04 MKSU MOUNTING 
04.01 The MKSU is designed for either table 
or wall mounting (using the MKWM Wall Mount- 
ing Kit), but is factory-configured for table mount- 
ing. For wall mounting instructions, refer to Para- 
graph 
04.20. 
04.10 
Table Mounting the M KSU 
04.11 
Since the MKSU is already configured 
for table mounting, the only requirement is to 
choose a suitable location and proceed to 
Section 100-020-250, Power Supply lnstalla- 
Con. 
04.20 
Wall Mounting the MKSU 
IMPORTANT: 
If one or more MOPlJ PCBs are required in 
the system, review Paragraph 07.20, MOPlJ 
Installation, prior to mounting the MKSLJ. An 
MCBL (MOPlJ receiving connector) for each 
MOPU to be equipped must be installed 
before the MKSU is mounted on the wall. 
04.21 
The same MKWM Wall Mounting Kit is, 
’ 
used for both MKSUs. Each kit consists of: 
-2-  
						

							INSTALLATION 
SECTION 100-020-200 
JUNE 
1983 
1 Drilling Template 
1 Back Plate 
1 Side Plate A 
1 Side Plate B 
2 
Side Angles 
12 Binding-head Screws 
04.22 Be certain that all parts are included 
before proceeding. 
04.23 In addition to those items supplied 
in the MKWM kit, six fasteners, suitable for the 
type of wall chosen, must be supplied by the 
installer. The fasteners will 
the wall mount bracket and 
A typical fastener would be: 
l/4-in. Toggle Bolt 
l/4-in. Molly Fastener 
l/4-in. Lag Screw be used to secure 
MKSU to the wall. 
04.24 Choose a suitable location for the 
MKSU on a surface of sufficient strength to 
support its weight. The MKSUs (fully equipped) 
weigh 
: 
STRATA Xl I: 52.0 lb (23.6 kg) 
STRATA XX: 72.6 lb (32.9 kg) 
04.25 Secure the template (Figure 4) to 
the mounting surface with tape, and perform 
the following steps: 
a) 
b) 
c) 
Be sure the template is at the proper height 
and use a spirit level to make sure it is level. 
Mark the locations of the six mounting holes. 
Use the locations marked “A” for STRATA 
Xl I and “B” for STRATA XX. 
Remove the template, and at each point 
marked, drill a hole suitable for the chosen 
fastener. 
04.26 Assemble and secure the wall mount 
bracket as follows: 
a) Attach the two side plates (A & B) to the back 
plate using four of the binding-head screws 
supplied with the kit (Figure 5). Note that 
three holes are provided on the right side of 
the back plate. Use the inner two holes for 
STRATA XII and the outer two for STRATA 
XX. (When arranged for STRATA XX mount- 
ing, the side plate will extend beyond the Paper TernplatE 
 Wall 
b 
B 
% A,B 
For STRATA Xl I 
. (A) 
‘t 
Fo
 STRATA XX 
FIGURE 4 IB) * ‘- ’ 
MKSU WALL MOUNTING KIT TEMPLATE 
Binding-Head , , 
Screws 
J i A._ 
Side Plate - 
B . 
Back Plate’ 
Side Plate B 
Side Angle 
w---- Fasteners 
Supplied Locally 
FIGURE 5-ASSEMBLED 
MKSU WALL MOUNTING KIT 
back plate.) 
b) Attach front plate to side plates with four 
binding-head screws. 
c) Insert two fasteners into the holes in the 
mounting surface that correspond to the key- 
-3-  
						

							INSTALLATION 
SECTION 100-020-200 
JUNE 1983 
d) 
e) 
holes in the back plate. Tighten them loosely 
so that approximately 3/8-in. gap remains be- 
tween the head of the fastener and the mount- 
ing surface. 
install the wall mount assembly by slipping 
the two keyholes in the back plate over the 
two fasteners installed in Step C. 
Install the lower two fasteners in the back 
plate and tighten all four fasteners securing 
the wall mount assembly. 
04.27 The MKSU must be prepared for wall 
mounting by reversing the back cover. This will 
locate the two mounting holes at the top of the 
MKSU. To reverse the back cover, proceed as 
follows: 
a) 
b) 
Loosen all seven screws securing 
cover (Figure 6). 
Remove and save the three screws 
in Figure 6, lift the back cover off. the back FIGURE 7-MKSU 
indicated d) Reinstall the back cover. Secure 
four loosened screws. 
FIGURE 6-MKSU 
c) Rotate the back cover 180” and realign it so 
the two mounting holes project above the 
MKSU (Figure 7). 
e) Reinstall and tighten the three 
moved earlier. it with the 
screws re- 
04.28 Refer to Figure 8, and complete the 
wall mount installation as follows: 
FASTENERS 
SUPP,LIED LOCALLY 
-4- 
WALL 
FIGURE 8-MKSU 
a) Rest the MKSU on the wall mount assembly 
and loosen the two screws located near the 
’ 
bottom of each side of the MKSU.  
						

							b) 
: 
c) 
d) 
e) 
f) 
Cl) 
SECTION 100-020-200 
JUNE 1983 
Loosely attach the side angles to the lower system operations and battery-protected RAM 
sides of the MKSU by sliding their keyholes for system data storage are located on the 
over the previously mentioned screws. AMMU. 
Ensure that the side angles are properly aligned 
with the holes in the mounting bracket and 
that the two top holes are aligned with the 
holes in the mounting surface. CRDU: 
Fasten the MKSU to the mounting surface 
loosely, using the locally-supplied fasteners 
through the upper mounting holes. This optional PCB provides the additional 
memory capacity required for the Automatic 
Dialing-Station feature. The RAM containing 
the additional memory capacity is battery- 
protected. The CRDU mounts directly on the 
MCBU and/or MDSU. A maximum of two 
CRDUs are used in STRATA XII, while 
STRATA XX may use as many as three. 
Using four of the provided binding-head 
screws, secure the side angles to the wall 
mounting bracket. MCBU: 
Tighten the screws holding the side angles 
to the sides of the MKSU. 
Tighten the fasteners securing the MKSU to 
the mounting surface. Contains a microprocessor and serves to off- 
load the main CPU by processing routine 
and repetitive data transmission tasks to and 
from the peripheral equipment. One MCBU is 
used in STRATA XII, while two are required 
in any STRATA XX system that is equipped 
with more than 32 stations. 
04.29 Prior to installing any printed circuit 
boards, install the power supply per instructions 
in Section 100-020-250, Power Supply Installation. 
05 PRINTED CIRCUIT BOARDS 
05.01 Complete with all available options, 
both STRATA systems utilize 15 different PCBs, 
with a maximum of 18 for STRATA XII and 32 
for STRATA XX. They are: 
MPRU - one per system: 
Performs several system functions: 
l Provides connection points for the 24 
VDC input power. 
l Houses the voltage regulators that provide 
12 and 5 VDC for system operation. 
l Houses circuitry and connection points 
for the relay services and music-on-hold 
(MOH). 
l Houses the external page amplifier. 
MCAU/AMMU: 
The AMMU is required and mounts directly 
on the MCAU to form a single unit. All system 
control functions are performed by the single 
chip microprocessor located on the MCAU. 
The system program stored in ROM, RAM for 
INS IALLHl IUN 
MINU: 
Generates system tones and provides the 
switching matrix for the delivery of tones for 
both paging and intercom connections (one 
per system). 
MCOU (MF or DP): 
An interface between the MKSU and the 
public telephone network or PBX lines. De- 
pending upon local CO requirements, an MF 
or DP type of MCOU will be provided (MF 
for DTMF outpulsing, DP for rotary dial 
outpulsing). Each MCOU serves up to three 
CO/PBX lines. 
MSTU: 
An interface between the MKSU and EKTs, 
which includes a portion.of the system’s solid- 
state space division matrix. Each MSTU PCB 
services up to eight EKTs. 
MXPU: 
Contains the solid-state crosspoints that make 
up the remainder of the space division switch- 
ing matrix. Each MXPU services up to 16 
stations and provides access to 12 CO lines 
plus intercom or nine CO lines, depending 
upon its position in the system. 
MDSU: 
An optional PCB that serves as an interface 
between the DSS console(s) and the MKSU 
-5-  
						

							INSTALLATION 
SECTION 100-020-200 
JUNE 1983 
(each system uses only one MDSU). The MDSU 
serves up to two fully functional DSS consoles 
and two DSS consoles which are used as Busy 
Lamp Field terminals only. 
MSMU/S&J: 
The SCNU is required and mounts directly 
on the MSMU to form a single unit. This 
optional PC6 serves as an interface between 
the MKSU and a printer or storage device 
used for the SMDR feature. The PCB is equip- 
ped with an RS 232C-type interface (one 
per system). 
MOPU (MF/DP or DP): 
An optional PCB that serves as an interface 
between the MKSU and conventional, single 
line telephones or off-premise extension 
(OPX) lines. An MOPU DP will operate with 
rotary dial telephones only. Either DTMF or 
rotary dial telephones can be used with an 
MOPU MF/DP PCB. Each MOPU services 
two extensions. A maximum of two MOPUs 
can be installed in STRATA XII and three 
in STRATA XX. 
NOTE FOR DTMF TELEPHONES: 
l DTMF telephones cannot be Toll Re- 
stricted. 
l SK40 R cannot capture a telephone number 
dialed from a D TMF telephone; however, 
the remainder of the call details will 
be recorded. 
MPLU (MF or DP): 
The MPLU PCB is a special assembly of a POPU 
PCB mounted on an MCOU to form a single 
unit. This optional PCB allows the bridging of 
a CO/PBX line (which appears in the STRATA 
system) with a conventional telephone. “OPL” 
telephones thus connected will then auto- 
matically cause a busy indication within the 
STRATA system and establish system privacy 
when initiating or answering a call on the 
dedicated CO line. Each MPLU serves up to 
three CO/PBX line/OPL combinations and re- 
places the MCOU PCB that would usually serve 
these lines. Maximum is one MP LU per system. 
05.10 
MPRU’ PCB 
Options 
05.11 
The MPRU houses several options that 
must be considered before it is installed in the 
MKSU, they are: Background Music Relay Service: 
An optional BR relay (Kl socket, Figure 
9), if installed, piovides a dry contact at the 
BR terminals on the front of the MPRU to 
control cut-off of BGM during an external 
page. The relay operates whenever an external 
page occurs. (A BR relay is required only when 
BGM is provided via a page amplifier mounted 
externally.) 
FIGURE 9 
MPRU RELAY SOCKETS & W3 STRAP 
Night Relay Service: 
An ‘optional NR relay (K2 socket, Figure 9), 
if installed, provides a dry contact at the 
rVR 
terminals on the front of the MPRU. TheW3 
strap option (Figure 9) allows the relay to 
function in one of two modes. 
a) 
b) 
Answering Machine Control - if the W3 
strap remains intact, the relay is operated 
continuously when the system is in night 
service. This mode is intended for indirect 
control of an answering machine. 
Night Bell Control - if the 
W3 strap is 
cut, the relay pulses at a 1-sec. on, 3-sec. 
off rate whenever the system is in night 
transfer mode and an incoming call is 
ringing the system. This mode is intended 
to be used for indirect control of an ex- 
ternal night bell. 
External Page Impedance Selection: 
The external page output appears at the ter- 
minals labeled 8/600 on the front of the 
i 
MPRU. The output impedance can be selected -’ 
-6-