Toshiba Strata Xii, Strata Xx General Description Manual

							GENERAL DESCRIPTION 
SECTION 100-020-100 
JUNE 1983 
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All Call Voice Page 
Automatic Callback 
TABLE B 
STANDARD FEATURES 
SYSTEM 
0 
(Interc0m)i.l. I-Z 
_* 
Group Paging -- 
Live System Programming 
Message Waiting 
Multiple Simultaneous Handsfree Intercom 
Paths 
Music-on-hold Interface d 
Night Ringing Over External Page 
Night Transfer 
Non-blocking Dialing 
Outgoing Call Restriction 
PBX Compatible 
Private CO Lines 
Repeat Last Number Dialed 
Tenant Service ._: 
Toll Restriction 
Voice or Tone Signalling  Automatic Dialing-System -. 
Automatic Hold Recall 
Automatic Privacy 
Automatic Release from Hold 
Background Music with Station Control 
Busy Override 
Conference-Multi-station 
Conference-Multi-trunk 
Directed Call Pick-up r’ 
.: 
Distinctive Ringing 
DTMF and Dial Pulse Compatible 
External Page Interface 
Flash Key-PBX Transfer or CO Dial Tone 
Recall 
Flexible Line Ringing Assignment 
STATION 
Do Not Disturb 
Do Not Disturb Override 
Executive Override of Privacy 
Handsfree Answerback 
l-called Illumination 
l-hold Illumination 
l-use Illumination 0 
a 
0 
l 
0 
l 
Modular Handset and Line Cords 
Mute Key 
On-hook Dialing 
Push-button Dialing 
Ringing Line Preference 
Speakerphone 
TABLE C 
OPTIONAL FEATURES 
l Automatic Dialing-Station 
0 Direct Station Selection Console: 
l All Call Voice Page 0 
l Automatic Line Hold 0 
l Expanded Line Appearance 
l Multiple DSS Consoles 0 
l Night Transfer 0 
l Voice or Tone Signalling xG ,;,./ ,L _I ._ ;’ G 0 
l Off Premise Extension (OPX) _= :., ,I 
l Off Premise Line(OPL) . . . _ ‘_ .___r 
-. ._ 0 
_.. ; 0 
_, 
Relay Service 
l External Page 
l Night Relay Service 
Station Message Detail Recording Zt r-_z_. r >’ 
- T _ 
(SMDR) Li
						

							GENERAL DESCRIPTION 
SECTION 100-020-100 
JUNE 1983 
MKSU (STRATA Xl,“& XX) 
t - 
To CO 
25Pair 
Cable -1 Tunei ] 
External 
Speaker 
/ 
r 
MDF 
DSS 
J 
P-Pair 
FIGURE -8 -SYSTEM DIAGRAM 
._ 
: 
-IO-  
						

							05.02 Functional block diagrams of the systems 
are shown in Figures 9 (STRATA XII) and 10 
(STRATA XX). The systems, which are nearly 
t f identical, consist of: station interfaces (MSTU), 
which include a portion of the solid-state switch- 
ing matrix; the MXPU PCBs, containing the re- 
mainder of the switching matrix; the CO line 
interfaces (MCOU); the intercom circuits (MINU); 
DSS interface (MDSU); power, paging and MOH 
- interface (MPRU); the central control consisting 
of the MCAU/AMMU (the AMMU PCB mounts 
directly on the MCAU and is required in all sys- 
tems) and MCBU (STRATA XX uses two MCBUs, 
STRATA XII, only one); off-premise extension 
(OPX) interface (MOPU); and the SMDR interface 
(MSMU): 
05.03 The systems are entirely under the 
control of a single chip microprocessor, located, 
along with the system program and data memories, 
on the MCAU/AMMU PCBs. The MCBU PCB 
houses the microprocessor used to transmit and 
receive data to and from the other PCBs. 
06 SYSTEM CONFIGURATION 
06.00 Key Service Units 
06.01 The MKSU arrangements illustrated in 
Figures 3 (STRATA XII) and 4 (STRATA XX) 
show the locations of the various PCBs. All PCBs 
slide in from the front of the cabinet, and, al- 
though the rear panel of the MKSU is removable, 
rear access is usually not required. 
06.02 Complete with all available options, 
the STRATA systems utilize 12 different printed 
circuit boards. The functions of these PCBs are: 
MCOU(MForDP):( 
. !-_-. .=:I= : 2) 
An interface between the MKSU and the public 
telephone network or PBX lines. Ring detection, 
hold and dial outpulsing are performed by this 
PCB. Depending upon local CO requirements, 
an MF or DP type of MCOU will be provided 
(MF for DTMF outpulsing, DP for rotary 
dial outpulsing). Each MCOUPCB serves up to 
three CO/PBX lines. 
-- 
MSTU: 
- 
i:. rr- ‘;T )  _. ;_ , z, ,__: __ 
An interface‘ b&we%“th-e “-MKSU and EKTs, 
which includes a portion of the system’s solid- 
state space division matrix. Each MSTU PCB 
services up to eight EKTs. Two-pair wiring is 
required for each EKT; one pair carrying voice 
-ll- 
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ULlYCnn~ ucau-ut- I IUI~ 
SECTION 100-020-100 
JUNE 1983 
and the other pair carrying data to and from 
the EKT. 
MXPU: 
Contains the solid-state crosspoints which make 
up the remainder of the space division switch- 
I 
ing matrix. Each PCB services up to 16 stations 
and provides access to 12 CO lines plus four 
intercom paths, or nine CO lines and two inter- 
com paths, depending upon its position in the 
system. 
l . 
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, the RAM 
for system operations and the battery-protected 
RAM for system data storage are located on 
the AMMU. 
MCBU 
: 
Contains a microprocessor and serves to off- 
load the main CPU by handling the 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. 
CRDU: 
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 
CRDUsareused inSTRATAXII,whileSTRATA 
XX may use as many as three. 
MDSU: 
An optional PCB that serves as an interface 
between the DSS console(s) and the MKSU 
(only one MDSU is used in each system). The 
MDSU serves up to two fully functional DSS 
consoles and two DSS consoles that are used 
as Busy Lamp Field terminals only. 
Ml NU 
: L_, ,. - ,:..> ._; -., I. 
-: -.. 
1; 
Generates system tones and provides the switch- 
ing matrix for the delivery of tones for both 
paging and intercom connections (one per 
system).  
						

							GENERAL DESCRIPTION 
SECTION 100-020-100 
JUNE 1983 
1 MSTU MXPU EKT 
I I 
I DATA 
I 
I I  _-_ ____ 
I 
I I 
MCOU 
COIPBX 
LINES 
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1 I 1 I 
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: 
1 DATA 
MINU 
L I I 
I 
I I I 
MCOU ; ’ I 1 
I 
I 
DSS 
CONSOLE 
’ MDSU 
MPRU 
i EXTERNAL 
11 ; SPEAKER 
I 
MCBU 4 
1 Data MCAU 
Tl + 24V 
I RADIO 
/ 
+ 12v 
4 
POW 
-----I 
+5v POWER 
_ SUPPLY I 
AC 115V 
FIGURE g-STRATA XII FUNCTIONAL BLOCK DIAGRAM ’ 
__ 
: 
-12-  
						

							GENERAL DESCRIPTION 
SECTION 100-020-100 
JUNE 1983 
5 
MSMU _ 
I 
l-l,_ e;ni MSTU MXPU 
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?5 I 
XP XP - 
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) MINU, DATA 1 / , 
IL. 
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I 
I I 
MCOU 
COlPBX 
I- 
1 
LINES I >c 
c 
DSS 
CONSOLE 
MCBU( A 
MCBU 4 4 Data Mc*U 1 
SPEAKER 
MPRU 
EXTERNAL 
1;7 zv ! 1-1 1 1 RADIO 
I_ - - -1 
AC 115v 
FIGURE lo-STRATA XX FUNCTIONAL BLOCK DIAGRAM 
. . 
-13-  
						

							GENERAL DESCRIPTION 
SECTION 100-020-100 
JUNE 1983 
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 VDC 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. 
MOFVJ (DP or MF/DP): {L_- I ,,.“I .< ,. .I;,- ; 
-_ s 
r ‘! 
An optional PCB that serves as an interface 
between the MKSU and conventional, single 
line telephones or off-premise extension (OPX) 
lines. Each MOPU PCB services two extensions. 
A maximum of two MOPUs can be installed 
‘2. 
_ in STRATA XII and three in STRATA XX. 
An MOPU DP will operate with rotary dial- 
type telephones only. Either DTMF or rotary 
dial telephones can be used with an MOPU 
MF/DP PCB. 
MSMU/SCNU : 
il 
, _.*.-;.- / 
;: -IThe SCNU is required and mounts directly on 
;:i ‘,. 
the MSMU to form a single unit. This optional 
_: 
, _ .- -PCB serves as an interface between the MKSU 
_ and a printer or storage device used for the 
SMDR feature. The PCB is equipped with an 
RS 232C-type interface (one per ;syFem). 
:)“iC i ,. 
- _ 
I - 
MPLU/POPU (MF or DP): 
The POPU is required and mounts directly on 
the MPLU 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. OP L telephones 
thus connected will automatically cause a busy 
indication within the STRATA system and 
establish system privacy when initiating or 
answering a call on the dedicated CO line. The 
MPLU serves up to three CO/PBX line/OPL 
combinations and replaces the MCOU that 
would usually serve these lines. A maximum 
of one MPLU may be used per system. 
06.10 Power Supply Assembly 
06.11 The separate power supply is a fixed unit 
complete with a wall .mounting bracket. Attach- 
ment to a wall or other fixed surface is via two % inch toggle bolts or screws, The unit can accom- 
modate “brown out” conditions or high voltages 
within a range of 90 ‘Q 
130 VAC, 60 Hz. A lo-ft. 
AC power cord allows flexibility in lpcating the 
power supply during installation. 
06.12 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 and is connected to the recommended 
battery pack (which is customer-supplied, consist- 
ing of two 12 VDC, maintenance-free, automobile 
type batteries - 80 amp/hour maximum rating). 
With the optional battery back-up assembly 
installed, all functions of the STRATA systems will 
continue to operate for several hours (the actua! 
time period is in direct ratio to the type and size 
of batteries selected) after a loss of normal elec- 
trical power. No calls will be disconnected during 
switch-over to battery power. 
06.20 Station Equipment 
06.2 1 Standard electronic key telephone (EKT) 
features include full speakerphone capability, 
handsfree answerback and modular handset and 
line 
cords. 
06.22 The principal components of the 
STRATA 20-key EKT are: handset, dial pad, 
speaker, ringing volume control, speakerphone 
volume control, intercom key, 17 CO/PBX line 
keys (or with up to seven Automatic Dialing keys) 
and six feature keys. LED indicators are provided 
for all keys except the HOLD, CONF and MUTE 
keys. 
06.23 In addition, 
software options allow 
complete compatibility of the STRATA VI EKT 
with both of the STRATA XII & XX systems. 
This lo-key EKT will have direct access to seven 
CO/PBX lines, but can receive transferred calls 
on all other unrestricted CO/PBX lines. 
06.24 The optional lo-key BLF EKT may 
be assigned via software at up to 15 positions 
(stations 10 through 25, except #17, only). This 
EKT has the same dimensions and key features as 
the 1 O-key. 
06.25 An optional Direct Station Selection 
(DSS) console is available for both systems where 
the volume of incoming calls warrants a dedicated 
call forwarding location. The dimensions of th 
DSS are the same as the EKT. The attendant _ 
-14-  
						

							EKT varies from the standard EKT only in dif- 
ferent dedicated key functions and lacking an 
intercom key (it is on the DSS). The DSS is e- 
quipped with up to 56 station keys, an intercom 
key, an All -Call page key, Message Waiting/Flash 
key and a Night Transfer key. Either system may 
be equipped with one or two fully functional 
DSS consoles. 
06.26 One or two DSS consoles may be option- 
ally added to either system as BLF consoles. Their 
only function is to provide station status 
information. 
06.27 Utilizing the 20-key EKT, thirteen 
different configurations of line and feature assign- 
ments are available. Some options include 17 
CO/PBX lines, while others offer up to seven Auto- 
matic Dialing keys with a corresponding reduction 
in available 
CO/PBX keys. 
06.28 The lo-key EKT offers five variations 
of key assignments, which differ only in CO/ 
PBX line appearance. 
06.30 Installation 
06.31 The STRATA MKSUs are arranged at 
the factory for table-top mounting, but the use 
of the optional wall mount bracket and a simple 
reversal of the back panel quickly converts them 
for wall mounting. 
06.32 All connections to the MKSUs are made 
via the faceplates of the various printed circuit 
boards. 
l CO/PBX line connections are made to the 
front of each MCOU using one 3-pair mod- 
ular cord for each card. 
l Each group of eight EKTs is connected to the 
front of each MSTU with one standard 50-pin 
amphenol-type connector. 
DSS connections are made to the front of 
the 
MDSU PCB with one 2-pair modular cord 
for each DSS. 
Screw-terminal barrier strips are mounted 
on the front of the MPRU to provide attach- 
ment points for the following connections: 
24 VDC power input 
Music-on-hold source input 
-15- GENERAL DESCRIPTION 
SECTION 100-020-100 
JUNE 1983 
External page output - 
Night relay service 
External page relay service 
l An RS 232C-type plug is provided on the 
MSMU for connecting the SMDR printer; 
l OPX connections for two circuits are made 
to the front of the MOPU PCB by using a single 
2pair modular cord. External DC and ringing 
power, is connected to the&lOPU via a screw- 
terminal barrier strip. 
l OPL connections are made via 6-wire modular 
cords to the front of the MPLU. Two cords are 
required; one cord is connected to the CO jack 
and serves up to three CO/PBX line connec- 
tions as with an MCOU (the MPLU occupies 
an MCOU PCB position), the second 6-wire 
cord connects to the OPL jack and serves the 
three OPL stations provided by that PCB. 
06.33 The power supply is mounted to the 
wall separately from the MKSU and connected 
to the 24 VDC input on the MPRU PCB. 
06.40 Maintenance 
06.41 Faults in both STRATA systems are 
repaired by replacing any faulty component (PCB, 
subassembly, telephone, etc.) and returning it to 
the manufacturer for repair. 
07 FEATURES and OPERATION 
07 .oo General 
07.01 This section contains brief descriptions 
of the STRATA features listed earlier in Tables B 
and C and some associated operating instructions. 
Detailed operating instructions can be found _in 
the STRATA XII and XX USER GUIDE or 
Section 100-020-400, operating 
Procedures. 
07.10 
Standard Features 
07.11 
System 
All Call Voice Page: 
Dialing a 2-digit access code permits a station 
user to page via all EKT speakers simultane 
ously. The system can also be programmed to 
include the External Page feature in an AH 
Call Page.  
						

							GENERAL DESCRIPTION 
SECTION 100-020-100 
JUNE 1983 
Automatic Callback (Intercom) : 
Permits a station user who encounters a busy 
station on intercom to request a callback by 
dialing a dedicated access code. The system then 
monitors the called station and signals the caller 
when it becomes idle. 
Automatic Dialing-System: 
This standard feature allows 24 numbers to be 
stored in the system memory. After selecting 
an outgoing line, any station user can cause 
one of the stored numbers to be outpulsed 
by dialing the proper access code. 
Automatic Hold Recall: 
A CO line placed on hold by any station will 
recall that station after a programmable period 
of time. 
Automatic Privacy: 
Privacy is automatic on all connections (except 
OPL). 
Automatic Release from Hold: 
The system automatically releases held CO lines 
if a disconnect signal is received from the 
central office. 
Background Music with Station Control: 
Music from the music-on-hold source can, at 
the station 
user’s option, be heard via the EKT 
speaker. The same music may also be broad- 
cast via the external page interface if an external 
speaker is installed. 
Busy Override: 
After dialing a 
busy station and receiving a busy 
tone, the caller can dial a 
q and cause a tone 
burst to be sounded via the called EKT speaker. 
Conference-Multi-station: 
Conferencing is permitted to a maximum of 
four stations and one CO or intercom line. 
Conference-Multi-trunk: 
Conferencing of two CO lines and three stations 
is permitted. 
Directed Call Pick-up: 
Intercom calls can be answered from any station 
by going off-hook, without siezing a line, and 
dialing the number of the ringing station. 
Distinctive Ringing: 
CO line and intercom calls are distinguished by 
different ringing tones. DTMF and Dial Pulse Compatible: 
DTMF or rotary dial pulse signalling can be 
sent to the CO/PBX line by installing the proper 
., MCOU PCB type. 
External Page 
Interface: 
Dialing a 2-digit code permits a station user 
access to a customer-provided external speaker 
via an internal 3-watt amplifier. As an option, 
a 2-way, 600-ohm voice path is available for 
use with a customer-supplies talk-back speaker/ 
amplifier. 
Flash Key-PBX Transfer or CO Dial Tone Recall: 
All EKTs are equipped with a Message Waiting/ 
Flash (MW/FL) key which, when operated while- 
connected to a CO/PBX line, causes a timed 
“flash” to be transmitted to the CO or PBX. 
The timing of the flash can be programmed to 
signal a PBX for feature operation or can be 
long enough to cause a disconnect and dial 
tone recall on a CO line. Also see Message 
Waiting. 
Flexible Line Ringing Assignment: 
A programmable ring or no ring option is pro- 
vided for each line selectively by each station. 
Each line may be programmed to ring a max- 
imum of eight stations. 
Group Paging: 
Special 2-digit access codes (81, 82, 83 or 
84) permit voice paging to one of four zones. 
Zone assignment is via software and is totally 
flexible. Paging is via the EKT speakers. 
Live System Programming: 
Live system programming is accomplished 
without service interruption to other station 
users by placing the system in the special pro- 
gramming mode and inputting data via station 
17. Station 17 is the only station that is “down” 
during programming. 
Message Waiting: 
The designated Message Center can indicate 
a message is waiting for any station with the 
Message Waiting LED of that station. The called 
station cancels the LED by lifting the handset 
and operating the MW/FL key. Also see Flash 
Key. 
Multiple Simultaneous Handsfree Intercom Paths: 
Four intercom paths are available in a STRATA 
XII system and up to six paths in a STRATA 
-16-  
						

							XX. All intercom lines are able to carry hands- 
free conversations simultaneously. 
Music-on-hold Interface: 
An interface is included for a customer-provided 
music source. CO lines placed on hold will be 
connected to this source. In addition, this music 
may also be broadcast from EKT speakers 
and external page when the background music 
options are selected. 
Night Ringing Over External Page: 
As a programmable option, while the night 
mode is active, a system-generated ring tone 
will be transmitted via the external speaker 
whenever any line rings (see Tenant Service). 
Night Transfer: 
On a programmable optional basis, the STRATA 
systems can function with two or three ringing 
patterns. If three patterns are selected, they 
are designated Day, Day 2, and Night. If only 
two patterns are selected, Day and Night desig- 
nations are used. In both cases, the ringing 
modes are selected with the lNrl key on either 
DSS console or station 10 (see Tenant Service). 
Non-blocking Dialing: 
Dialing is permitted on INT and all CO lines 
simultaneously. 
Outgoing Call Restriction: 
Any station can be selectively restricted frqm 
originating calls on any or all CO lines. However, 
the station may still receive calls on the res- 
tricted line(s). 
PBX Compatible: 
STRATA features, 
automatic dialing, 
operation. 
Private CO Lines: 
Restrictions may 
system so selected such as toll restriction and 
are compatible with PBX 
be programmed into the 
co line(s) will appear only 
on selected station(s). 
Repeat Last Number Dialed: 
The last number dialed by each station is always 
stored by the system and will be dialed auto- 
matically whenever the station user selects 
an outgoing line and depresses the 
q key. 
Tenant Service: 
Variable CO/PBX line key assignments allow 
GENERAL DESCRIPTION 
SECTION 
100-020-100 
JUNE 1983 
two tenants to be served from the same MKSU 
with each tenant’s lines appearing in the correct 
sequence. When Tenant Service is used, Night 
Ringing Over External Page will apply to lines 
assigned to Tenant #l only. Also, Night Trans- 
fer of Ringing for Tenant #1 and Tenant #2 
lines will be independantly controlled by DSS 
#1 (station 10) and DSS #2 (station 
1 l), 
respectively. 
Toll Restriction: 
Selectively programmed on i per-station, per- 
line basis, STRATA performs 
toll restriction 
by rejecting the numbers “0” and “1” as the 
first or second digit and limiting the total 
number of digits dialed to seven or eight. 
Voice or Tone Signalling: 
A programmable system feature that optionally 
selects either tone ringing or voice page as the 
primary method of intercom call signalling. 
The calling station, however, may choose the 
alternate method by dialing /J following the 
station number. 
07.12 
Station 
9 
Do Not Disturb: 
This feature is activated and deactivated by 
alternate depressions of the @ key. A 
station calling a station that is in the DND mode 
will receive a fast busy tone. 
Do Not Disturb Override: 
After reaching a DND station, that station may 
be advised that a call is waiting by dialing 
q . 
A tone signal will be heard at the DND station. 
Executive Override of Privacy: 
A station that is programmed for this feature 
will override the automatic privacy feature and 
is able to enter any existing conversation within 
the system. A warning tone, however, is inserted 
before the overriding station is actually con- 
nected. A maximum of two stations can be 
programmed for executive override. 
Handsfree Answerback: 
All EKTs are equipped for handsfree answer- 
back on voice-announced intercom calls as 
a standard feature. 
l-called Illumination: 
A distinctive flash appears on the intercom 
LED at the EKT that is actually being called. 
-17-  
						

							GENERAL DESCRIPTION 
SECTION 100-020-100 
JUNE 1983 
l-hold Illumination: 
The EKT user is shown a distinctive LED 
flash to indicate a line actually placed on hold 
at the EKT. All other stations see a normal 
on-hold-flash. 
l-use Illumination: 
A distinctive flash rate shows the line presently 
in use at a given EKT. Other stations see a 
steadly illuminated LED for that line. 
Modular Handset and Line Cords: 
All EKTs are equipped with modular handset 
and line cords. 
Mute Key: 
All EKTs have a II key that may be used to 
cut off the microphone when the speakerphone 
is in use, thereby permitting a private local con- 
versation. 
On-hook Dialing: 
STRATA lets you dial your calls with the hand- 
set still on-hook. Call progress can be heard 
via the telephone speaker; no need to pick up 
the handset until your party answers. 
Push-Button Dialing: 
All STRATA EKTs are equipped with push- 
button dial pads. 
Ringing Line Preference: 
A line ringing at a station can be answered by 
merely lifting the handset or depressing the 
(=I key. The ringing line will be automati- 
cally selected. 
Speakerphone: 
All EKTs are fully functional speakerphones. 
07.20 Optional Features 
Automatic Dialing-Station: 
Adding CRDUs to the MCBU and/or MDSU 
increases the STRATA automatic dialing capa- 
bilities from the standard 24 numbers in Auto- 
matic DialingSystem to a maximum of 40 
telephone numbers 
list and 40 numbers 
list. in the system directory 
in each station’s directory 
Direct Station Selection (DSS) Console: 
a) All Call Voice Page -a single dedicated 
key 
on the DSS console (labeled m ) will 
b) 
cl 
d) 
4 
f) 
allow the attendant to voice-page via the 
EKT speakers at all the stations in the 
system simultaneously. If the External Page 
has been included in the All Call -via system 
option selection, the m key will operate 
that as well. 
Automatic Line Hold-each calling CO/PBX 
line is automatically placed on hold when 
the DSS operator activates a station key. 
Expanded Line Appearance-twenty CO/ 
PBX line keys are available on the EKT 
associated with the DSS console. The 
intercom and -1 keys for that EKT 
are located on the DSS console. 
Multiple DSS Consoles-the STRATA XII 
and STRATA XX systems will each support 
two fully funtional DSS consoles (which 
may operate simultaneously) as well as two 
additional consoles functioning only as 
Busy Lamp Field terminals. 
Night Transfer-the lNTl key on the DSS 
console(s) or station 10 controls the system 
ringing patterns. 
Voice or Tone Signalling-the DSS may be 
programmed for tone or voice signalling 
preference independently of the remainder 
of the system. As with all stations, the 
operator can choose the alternate mode 
by dialing a !-?J following the station 
number. 
Off Premise Extension (OPX) 
: 
Installing an optional MOPU (DP or MF/DP) 
PCB, along with auxiliary power and ringing 
supply, allows the system to interface with 
conventional single line telephones or off pre- 
mise circuits. The MOPU serves two extensions 
and a maximum of two may be installed in 
STRATA XII and three in STRATA XX. 
Off Premise Line (OPL): 
Installing an optional MPLU (MF or DP) in 
place of an MCOU PCB allows the bridging 
of a CO/PBX line (which appears in theSTRATA 
system) with a conventional telephone. Max- 
imum: one per system. 
Relay Service: 
When the optional relays are equipped on the 
MPRU PCB, the following 
signals are provided 
for external equipment: 
-18-