BT KINSMAN or Mitel SX 20

PXML No. 68
APPROVAL No. S/1412/23/C/020691 (SX20) & S/1000/23/C/020691 (KINSMAN)

Click here to see information on BT's withdrawal of Subscribers Private Metering (SPM)

The SX20 was made by Mitel and marketed by many companies as the SX20, except BT who called it the Kinsman.
The console is the same one used by the Mitel SX10E and although similar looking to that of the SX200 it is incompatible. The system will support LD and MF telephones with either earth or timed break recall. The Kinsman was withdrawn from BT's portfolio in 1988.

CAPACITY
The SX20 has a maximum configuration of 12 exchange lines and 72 extensions. These cannot be achieved at the same time due to the structure of the system and the real configuration could be described as either a maximum of 8+72 or 12+48 (this is described fully in the next chapter). The Superset 4 featurephone and 60 store repertory dial is only supported on software generic 543. A visually handicapped operator console is also available.

A Remote Display Unit (pictured to the left) and standard POT telephone can used instead of the Console.

The Mitel SX20 is an analogue, stored Programme Control (SPC) PABX employing Solid state space-division switching.  Much of the equipment incorporated in the SX20 system is common with other Mitel products.  The system consists of a metal Chassis and an impact-resistant plastic cover.

Simultaneous use of MF4, Rotary Dial and SuperSet 4 Featurephones is possible. with the use of MF4 or Rotary Dial phones being possible on any of the lines, Supersets, however can only be used on selected lines.

Automatic Diagnostics execute self checks of the system.  Detected faults raise audio and visual alarms.

240V 50hz Mains voltage is converted in the power supply unit to the voltages required by the system.

After a mains failure and exhaustion of the battery back-up power three extensions are connected to the public network, two automatically the third manually (See section on Equipment Provision Rules), under these conditions only Rotary Dial Telephones will function, unless the local exchange is capable of receiving MF4 digits, when MF4 telephones may be used.  SuperSets will NOT function during total power fail conditions.

A 27v dc feed is supplied to extension telephone instruments.

The PABX can be used as a host or subsidiary system in accordance with DTI specification 84/011.  Where used as a subsidiary, there may be a limited number of facilities available between the two systems.

CAPACITIES
The basic SX-20/KINSMAN system consists of a single cabinet containing:-
one off Central Processing Unit (CPU)
one off Universal Console Connector
Extension Card, equipped for 8 or 24 standard DP or DTMF telephones.
Miscellaneous Card, carrying:

• Tone Generators and Receivers
• Up to 4 Trunk Modules (8 Trunks)

The system may be extended with one or two more cards from the following:­

The trunk modules contain two circuits each and these may be Local Exchange Trunks (switchable for Earth or Loop Calling Protocols).  SSAC15A or SSD5E Trunks.

The SX20/KINSMAN can handle a maximum of twelve simultaneous calls.

The system may also include an operators console.
Various combinations of cards allow the system capacity to be varied up to the following limits:-
8 Trunks and 72 ordinary telephones
8 Trunks and 48 ordinary telephones plus 16 SS4 (TX14) Featurephones
12 Trunks and 48 ordinary extensions
12 Trunks and 24 ordinary telephones plus 16 SS4 (TX14) Featurephones

NOTES:
1. Any Individual Featurephone may be replaced by an ordinary telephone.
2. Supersets are available on Generic 543 Systems only.

The above was taken from the PXML

Click here for information on the RAM batteries

Click here for the Parts List

Cabinet key = FS880

INSTALLATION
Before use, the SX20 system must be loaded with default data.  This operation clears out the RAM and loads default data, ensuring that the database is free from corruption.

Loading Default data

1. Open cover
2. Set CPU switches 1 - 8 to required positions
3. Set battery switch on PROM board to ON (PROM board is fitted to CPU card)
4. Turn power on
5. Set CPU switch 8 on CPU card to closed
6. press RESET button (below DIP switches on CPU card)
7. Console display shows 88888888
8. Console display shows ????????
9. Within 6 seconds set CPU switch 8 to open
10. Console display shows --------
11. Set CPU switch 8 to closed
12. Console display shows 00-00
13. Default Data has been loaded

CPU DIP switch settings

CPU switch settings

Programming Mode
To enter programming:

1. Check that system DIP switch 8 is set to CLOSED
2. Press the status button until 542 or 543 appears and hold button down
3. Dial 7772
4. Release STATUS button
5. Dial 58 or #

Click here for advice on trouble shooting the SX20

REMOTE DISPLAY UNIT
The Remote Display Unit is supplied as a kit that comprises of two American style jacks and two connection cords.  A two pair cable is run between the two jack sockets.  On cord plugs into the Remote Display Unit and the other end plugs into the CCU motherboard.  The Display Unit is shown to the right and the table below advises on how to wire the unit.

Printer Lead Wiring

542 ALARMS
01 	Power up diagnostics test.
02	Power up or auto diagnostics test.
04 	Automatic diagnostics test.
05	Automatic diagnostics test.
10	TK condition. (No loop curr. detected on TKxx).
11	TK condition. (No seize ACK. when TKxx seized).
12 	TK condition. (No Release ACK. when TKxx Rlsd).
20	Sp/path stuck at 0 and busied out.
21 	Sp/path stuck at high and busied out.
22	Sp/path xx 5/cct. to Sp/path yy both busied.
23	Sp/path xx failure due to DT detector test.
30  	Unable to connect Sp/path to Extension xx.
31	Unable to connect Sp/path to TK xx.
40 	DT detector x failure and busied out.
4I  	MF4 gen. x failure and busied out.
42 	MF4 rec. x failure and busied.
50	P/fail & reset caused by internal working.
60-69	Software alarms.
63	Defective battery ram.
64	Corrupted non-volatile ram.
80	Trunk held up busy.

543 ALARMS
01 	Power up diagnostics test.
02	Power up or auto diagnostics test.
03      Volatile RAM read/write test error.
04 	Automatic diagnostics test.
05	Automatic diagnostics test.
10	TK condition. (No loop curr. detected on TKxx).
11	TK condition. (No seize ACK. when TKxx seized).
12 	TK condition. (No Release ACK. when TKxx Rlsd).
15      Extension equipment XX B wire permanent earth.
20	Sp/path stuck at 0 and busied out.
21 	Sp/path stuck at high and busied out.
22	Sp/path xx 5/cct. to Sp/path yy both busied.
23	Sp/path xx failure due to DT detector test.
30  	Unable to connect Sp/path to Extension xx.
31	Unable to connect Sp/path to TK xx.
40 	DT detector x failure and busied out.
4I  	MF4 gen. x failure and busied out.
42 	MF4 rec. x failure and busied.
50	P/fail & reset caused by internal working.
60-69	Software alarms.
63	Defective battery ram.
64	Corrupted non-volatile ram.
72      Console dead due to hardware failure or switching to console-less operation
80	Trunk held up busy & will not release.
90      Reader error (data dump and load).
91      Printer dead.
92      Auto wake-up queue full/CIL queue full.

Default Feature Access Codes