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Click here for the System Programming Guide

The Omnicom FS2828 is 2 line, 8 extension PABX suitable for domestic and small office use.

It has the following features:-

The box is mounted to a wall and connected to a mains supply via the supplied adapter. The external line(s) are connected directly to a BT socket. The only real work is in connecting the extensions. These connect via standard punch-down blocks, much like a normal telephone extension socket except there's eight of them

The system can be programmed from a standard touch-tone phone connected to any of the Omnicom's extension ports.

Voice Prompting
A synthesised voice guides you through the process of configuring the system, setting the clock, etc. It also has a speaking clock.

The Omnicom will work quite happily with one or two external telephone lines. The unit has two cables with standard BT phone plugs attached to connect to the separate telephone sockets. It has some useful features, for example, you can designate one of the lines to be a fax/data line, in which case incoming calls will be automatically directed to a nominated extension. However, when placing outgoing calls, the Omnicom will use whichever line is free, without any intervention, allowing two external calls at once.

Eight extension ports are provided with numbers 220 to 227. There are a number of options that can be specified for each extension, such as Call Barring, Auto-9, etc. For example, Jake has a phone in his bedroom on Extension 225. This has been programmed to allow internal calls and external calls from pre-programmed shortcut numbers only. The modem for the Internet Gateway is on Extension 227. This has Auto-9 enabled which means that it does not need to dial 9 to get an outside line first (these are all programmable features).

In the event of a power failure, an internal relay within the Omnicom will automatically connect Extension 220 to the telephone line. This ensures that at least one phone continues to work.

Call Handling
The Omnicom provides Call Hold, Transfer, Park and Divert functions.

Smoke Detector Connection
A port is provided that allows direct connection of a smoke detector, or other alarm device. This causes all internal phones to be called simultaneously in the event of an emergency.

Other Features
Speaking Clock, Do Not Disturb, Door Intercom and release interface.


1.        Caller ID information is not passed to any of the extensions. This means that any Caller ID devices need to be attached directly to the external line.

2.        After a power failure, a voice prompt is given whenever a phone is used reminding the user that the clock needs resetting.

With Acknowledgment to Steve Morgan.

Note: a lot of the programming which refers to things like 'Premium Rate' would be the Premium Rate numbers then in use when the system was produced i.e.  0898 and hence will not work with modern day codes.

The same applies to Phoneday and Prephone day versions of the software and codes in use at the time.

Omnicom Hints and Tips

1. Buzzing on all lines

Possible cause:-
Smoothing capacitors have failed.

The below should only be attempted by a suitably qualified competent person.

  1. Disconnect power from unit.

  2. Disconnect incoming phone lines.

  3. Disconnect all extension and other cables from front of unit.

  4. Unscrew 6 screws from back of unit and remove back, exposing the main board.

  5. Remove the main board, by pressing on the extension connecting blocks on the front of the unit lifting to 30 degrees then easing clear of the connectors at the top of the board.

  6. Unscrew 4 screws securing the power unit board, exposed by removing the main board.

  7. Replace all capacitors C6, C7 & C8 (1000uf 35v - RS Part Number 339-1038) or (C6 1000uF 35V CPC Part Number CA04937 pack of 5 and C7 & C8 2200uF 16V CPC Part Number CA04930 pack of 5) and C77 & C106 (470uf 120v - RS Part Number 339-7127).

  8. You may find it better to leave the "legs" on C77 & C106 and solder the new capacitors to these.

  9. You may also have to cut away some of the box interior to allow the refitting of the boards, as the new capacitors are larger than the old one (the CPC capacitors are a direct replacement and do not need modification).

  10. Reassemble the unit in the reverse order, taking care to ensure all connector pins, between the two boards, can be viewed through the small holes in the top of the main board.

2. Not connecting to answer party first time

Omnicom set to Pulse Dial and needs to be set to Tone Dial.

Enter programming mode by lifting any handset and press #2828 (default password).

  1. Press 91, the omni will respond by saying "Line 1 Pulse" or "Line 1 Tone". If the response was "Line 1 Pulse", re-enter 91 to set tone dialing.

  2. Press 81, the omni will respond by saying "Line 2 Pulse" or "Line 2 Tone". If the response was "Line 2 Pulse", re-enter 91 to set tone dialing.

  3. Put the handset down.

3. Problem setting Mercury 132 pin

There is an error in the manual.

After Entering * as the password you must enter a # to continue.

4. Unrecognized Number when using Mercury 132

* is dialled to line as the password, with older exchanges this was ignored however with modern exchanges it is processed as an invalid digit causing the .Unrecognised Number. message from the exchange.

Enter the Mercury password (Programming options 95 + 85) as 2 and program the Mercury Access Code (Programming options 96 + 86) as 13 (Omitting the 2).

5. Lost Pin / Fails to respond to user programmed pin and default #2828

Lost / forgotten pin OR power surge.

Remote reset is no longer available, it is suggested to disconnect from the mains for a minimum of 24hrs and try again (if this doesn't work then disconnect the RAM battery and then reconnect - at your liability).

6. Unexpected Results

Corrupted programming possibly due to power surge.

Reset the unit to factory defaults by entering programming mode and entering *9 then re-program all options.

7. Memory loss after power outage

Generally caused by RAM battery failure.

Replace RAM battery.
The battery is a 3.6v ni-cd. These are available from CPC (Part number BT00181).  It is suggested that the original battery be replaced with two long leads which are then connected to the ni-cd cell.  This will allow for easy replacement in future as it is can now be externally mounted.

Thanks to Terry Abrahams for the information on replacement of Capacitors and ni-cd battery and Mike Holdaway for the capacitor update.


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Last revised: December 03, 2018