The BT Merlin M2105 was manufactured by Acorn for British Telecom as a dedicated communications terminal. It is essentially an Acorn Electron and an expansion box that contains a modem, voice synthesizer, serial port and printer port.

 

The expansion box is bolted to the Electron and attaches to the expansion port.

 

They were supplied by BT to their engineers to allow them to communicate with each other and BT in a bulletin board and basic email way. However, this was pre internet and email as we know it today.

 

They may also have been supplied to BT customers including Interflora.

Dr Jeremy Klein comments

I was seconded from Logica to BT to help identify markets and applications for the M2105. It was in effect a messaging service over the PSTN.  At that time there were no established use cases. 

We looked at health and social services and a possibility because there was a need to communicate across organizational boundaries. 

For example, discharging a patient from hospital was something I studied as it involved the hospital and the local authority.  We did actually create a reasonable case for the M2105 in some specific applications such as these.  There was also interest in including a form of central server to gather statistics. 

I recall that BT was not really set up to sell this sort of technology and the people I worked with seemed to have come through the route of being engineers in local telephone exchanges.  So marketing was not their thing. 

Also, for the price, the M2105 looked rather poor quality and everyone could see that it was basically a home computer. The need to pay for a telephone call for each single message was also a drawback as at that time calls were expensive.

When the Acorn Electron Merlin computer is connected up on its own the message that comes up on the screen reads: "Acorn Electron" and underneath: "BASIC" When the BT Merlin expansion box is connected to the Acorn Electron Merlin computer the following message appears on the screen: MERLIN BUSINESS SYSTEMS M2105 Terminal 1 Version V3.50 16/02/87 (c) British Telecommunications plc 1986 sc21302130 sc21302130 _ printer (to remind operator to connect a dot matrix printer).

 

 
 

Acorn - BT Merlin M2105 Manuals:

Item	Manufacturer	Date
BT Merlin User Guide M2105 Messaging Terminal	BT	2 Jun 1985