Connected Earth: Smarter phones

As networks were getting smarter, so too were the phones and other devices being attached to those networks. To minimise the risk of equipment failure affecting basic telephone service, all advanced functions, like answering machines, were add-on pieces of equipment, installed separately from the main telephone. Combining this with smarter telephones equipped with digital displays allowed Caller Identification - displaying the number of the caller before you answered the call.
The switch to electronic and digital networks coincided with two other trends in technology - the miniaturisation of devices and the tumbling cost of processing. As networks were getting smarter, so too were the phones and other devices being attached to those networks. Before long, telephone users were able to do a range of things they'd never been able to before.

Adding functions : creating smarter telephones
Making something do more usually means making it more complicated - and therefore less reliable. This was a major consideration when most telephone repairs were carried out on the spot at customers' premises.

To minimise the risk of equipment failure affecting basic telephone service, all advanced functions, like answering machines, were add-on pieces of equipment, installed separately from the main telephone. That made it easier to disconnect and repair them if they went wrong.
The Card Callmaker was typical of the sort of add on device you could rent in the 1970s. It used plastic cards with holes punched by users corresponding to each frequently called number. Putting this card in the card reader device triggered an automatic dialler.
These days, cheap processors have made it far cheaper to integrate memory dial functions into the telephone - so cheap, in fact, that it's normally easier to replace the whole telephone if any part of it goes wrong.

The first stored numbers (1978) : one button ringback
'Smart' phones - telephones with a memory built-in - sound like a recent innovation but they go back a long way. Memory dialler attachments to normal dial phones were available before the Second World War but did not really catch on. The real revolution came in 1978 with the introduction of the X-Press Callmaker, a push-button telephone that stored ten complete phone numbers and could dial one of these - or the last number called - at the touch of a button.
These days, though, many people prefer to use 'Ringback'. This is an even more user-friendly feature introduced by BT in 1996. When a number is engaged, the system offers you the choice to select Ringback, by pressing 5, then hanging up. As soon as the line you're calling becomes free, the exchange will detect it, call the number for you and call you at the same time. No special telephone is needed since the facility is an 'intelligent network service' built into the exchange.

Caller display services : who's that calling?
The adoption of digital technologies into the phone system made it possible for computers to interpret and label the traffic moving through the exchange and out on the network.
For the first time there was a label attached to the call - the originating number.
Combining this with smarter telephones equipped with digital displays allowed Caller Identification - displaying the number of the caller before you answered the call. It also provided a record of the last person to call you (1471) and automatic callback.

IDA telephone (c. 1984) : providing the need for speed
ISDN was a revolution for consumers who wanted to share information. It allowed people to transfer information much faster than they had before, and in many ways was the first step towards the information superhighway. In 1984 this new technology, including the ISDN telephone, was still under research. In the event, a standalone ISDN telephone was soon identified as unnecessary and dropped. As a result this is probably the last surviving example of the Intergrated Digital Access (IDA) telephone.

ISDN gave users a chance to transfer information at much higher speeds than before and it was very useful for any business working with high-definition images. Advertisers, animators, newspapers and media agencies could send photos and films over the network rather than by courier. For this reason, their uses focused on data transfer to and from computer or terminal so there was no real demand for the telephone.