BT MARQUIS 1 and 2

PXML No. 49 (Marquis 1), No. 123 (Marquis 2)
APPROVAL No. S/2374/3/D/450230 (Marquis 1), NS/2374/3/H/452697 (Marquis 2)

The Marquis or Merlin S6022 was marketed by BT and came in 2 variants, the Marquis 1 (pictured left) and the Marquis 2. The system was made by Tie Communications Ltd (called the EK 612).

The Marquis 1 5+12 (A variant) was originally sold only in the London area but around mid 1985 was sold nationwide as a Marquis 1 6+12 (B variant) - later known as the Merlin S6022. The Mk 1 could not be expanded and was standardised as a 6+12 system.
The Marquis 2 could on the other hand be expanded from 2+8 to a maximum of 6+16 and had new style telephones.


Programming Guide

Marquis (or Merlin S6022) has a wall mounted central control unit and Box Connection. TX64 (standard), TX66 (executive), and S6022M (new executive) terminals. Maximum capacity is 6 exchange lines and 12 extensions.

Made by Tie Communications Inc USA.

TX64 S6022M

Approved for direct connection to the PSTN (loop disconnect or MF signalling ) or by working as a (List A) subsidiary system (loop disconnect or MF signalling) connected to a (List C) PBX.

To load default data:-

  1. Plug a terminal into extn 70 only
  2. Check that the LED is lit on the left hand side of the CCU
  3. Lift handset
  4. Press INT key
  5. Key # 08 (for LD trunks) or # 09 (for MF trunks)
  6. Replace handset

The following software levels are approved for use with Marquis:-

KSU (612 UK - KSU - A) 60013 A Issue level 01
KSU (612 UK - KSU - B) 60013 B Issue level 01 or 03
KSU (612 UK - KSU - C) 60013 C Issue level Yl, Y2, Y3 or 01
Where the Issue level is shown in the date box on the cover of the KSU as follows:-

Manuf Site Issue level Week Year
xx 01 xx xx


MDF  Wiring Colours LJU 2/3C
A White/Blue 3
B Blue/White 4
C White/Orange 5
D Orange/White 2
Marquis Equipment S6022A  5+12	             		       374921
Marquis Equipment S6022B  6+12          	               374922
Marquis Telephone S6022M (New Executive)                       375503
Marquis Wallbracket                                            870222
Line jack Unit 2/3C                                            870127
Line jack Unit 2/1A                             	       373901
Strips Connection 237A (used with PW's)                        314371
Marquis Telephone S6022E (TX66 Executive)                      374924
Box Connection 270B                                            374664
Marquis S6022 Handset (Only to be used with
TX64 Telephone manufactured before wk 4285)                    374938
Marquis S6022 Cord Connecting 4/518
(handset cord)                                                 374939
Marquis S6022 Cord Connecting 4/517 (line cord)                374940
Marquis S6022 Part No. I/DCO 964 (key top)                     374941
Tone Caller 12A                                                870217
Marquis S6022 Handset (New Type KIA)                           870278
(only to be used on TX64 Telephones where last 4 digits
of date code show "4285" or later, and TX66 telephones
where the 3rd digit of date code is "X")
Fuse 36A/0.5 Anti-surge (late CCU'S)                           310755
Fuse 36A/1.0 Anti-surge (early CCU'S)                          320196

Marquis 2

Programming Guide

Marquis II is a replacement for the Marquis (S6022) Call Connect System.

It is a Key Telephone System with a maximum capacity of six exchange lines and sixteen extensions. It is supplied as a 6 + 8 system which can be expanded to its full capacity by the addition of an extension expander card. Three terminals are available, Standard (monitor), Handsfree and Handsfree with Busy Lamp Field and Direct Extension Select (BLF/DES).


  • Call hold and transfer

  • Abbreviated dialling

  • Night service

  • Call divert

  • 10 number memory per extension

  • 20 number memory system wide

  • Call barring

  • Paging

Made by Tie Communications

Approved as described in PXML 123 which is updated as further enhancements are approved. Only modifications and facilities specified as approved in PXML 123 are permitted.

Approved for direct connection to the PSTN (loop disconnect or MF signalling) or by working as a (List A) subsidiary system (Loop disconnect or MF signalling) connected to a (List C) PBX.

The system will support either Earth loop or Time Break Recall.

SOFTWARE - The software levels approved for Marquis II are BRuoui and BRG008 which can be identified by the EPROM label on IC U3 on the Main PCB as follows:-


PCB's and terminals have a warranty of 18 months from the date of manufacture which can be identified by the code marked on each item as follows:-

Terminals (8 digit code)
21Y11589 - Where 21 identifies the Manufacturer, YI the Build Level and 1589 the week and year of manufacture.

PCB's (4 digit code)
1589 - Where 15 identifies the week and 89 the year of manufacture.

Marquis II Central Control Unit                       375513
Marquis II Extension Expansion Card                   375514
Marquis II Standard terminal                          375515
Marquis II Handsfree BLF/DES                          375516
Marquis II Handsfree Terminal                         375517
Line Jack Unit 2/3C                                   870127
Line Jack Unit 3/3C                                   870257
Line Jack Unit 2/1A                                   373901
Marquis II 2+8 Backplane                              375537
Marquis II Line Expansion Card                        375538
Marquis II MDF Card                                   375539
Marquis II Handset Cord                               375540
Marquis II Handset                                    375541
Marquis II Line Cord                                  375542
36A/0.5A Anti-surge                                   310755


Terminals have to press the MEM key to receive internal dial tone or answer internal calls. Resetting the terminal clears the fault.

It was found that the fault was cleared by remaking all connections and terminations between the CCU and LJU2/3c. The cause of the problem therefore, is thought to be HR wiring, normally unregistered in a DC test but cleared when re-terminated.

If difficulties are still experienced, logical replacement of LJU, Tele cord, strips conn. etc. will be necessary.

Marquis I sites, with the London Code Change software, must have the National Code Change software fitted. Sites fitted with the London Code Change software were labelled as such and they contain the BR7030 V3.0 EPROM.

The fault symptom can also present itself as 'Marquis II terminals operating as Marquis I terminals on internal calls'.

The scenario is as follows:-
Extension A calls extension B and receives ring tone. B lifts handset to answer but cannot be heard by A, while A can speak normally to B. If at this point, B keys 'MEM' , the conversation can proceed as normal.

Once this fault is established, the called extension, (B in this case), will need to key MEM on all internal calls received subsequently. BLF/DSS Terminals can experience difficulties using the DSS keys such as 'no tone' and 'no signals'. External calls are not affected on any terminal.

The fault can be cleared by resetting the terminal. Changing the terminal and/or CCU will not provide a permanent clear. The changing of equipment cannot be approved of at this time as it is recognised that this will not provide any long term advantage.


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Last revised: October 30, 2022