As everyone knows, communication - and developing ways to improve it - between people has
always been, is, and very likely will remain being one of the most important fields in the
development of technology of the civilized world. The purpose of this document is to clarify the what's, why's and how's of the development of telecommunication technology from ancient times to foreseeable future.
Even the most primitive of human cultures in ancient history developed some ways to
communicate with each other, from guttural sounds and facial expressions to body moves and
gestures. In addition, there has always been a need to communicate with others across an
arbitrary distance, for instructions and orders while hunting etc.
At first, the means for long-distance communication were very crude and inefficient - also
unreliable - but, they worked. There were three main means used:
- noise (megaphones, church bells, cannons etc.)
- optical effects (heliographs, watch towers and smoke signals, flashlights and
- physical delivery (runners, horses, stage coaches, carrier pigeons, later on trains and
other motor vehicles)
Telegraph, invented in 1838, was taken into wide use six years later, in 1844, when Samuel
F.B. Morse introduced his revolutionary new language - the Morse code. During the same
year, the very first long-distance telegraph message was sent between Baltimore and
Washington. What made telegraph such breakthrough was the incredible speed, at which data
could be transmitted; nearly at the speed of light.
Here is a small comparison chart, to compare the various historical telecommunication methods
in a modern way:
Method Data rate Msg speed "repeaters" product
Carrier pigeon ~10 kbit/pigeon 70 km/h 700 km 150 kbit-m/sec
Megaphone 100 bits/sec 1000 km/h 2 km 30 bit-km/sec
Train Very high/train 70 km/h Virtually very high
Telegraph 100 bits/sec Very high 20 km 1 kbit-km/sec
With short messages, telegraph was far superior compared to any of the earlier methods, due to
its very high transmission speed. The intrinsic error rate of the telegraph was very low
and, in case of errors, re-transmission was easy and quick. Also, telegraph was relatively
cheap, and it was not man-power intensive.
Carrier pigeon turned out to be rather efficient as a telecommunication method by its
calculational bandwidth-distance product (although that does not tell much, since the
intrinsic error rate is not taken into account). Carrier pigeon media was relatively fast, it
could deliver a relatively large amount of data at once and the intrinsic error rate is
virtually zero (all errors made were transmission-media independent human errors).
Megaphone was a very unreliable transmission media, mainly due to its very limited range of
about a mile or two, if the weather was good and there was little or no wind. Thus,
it was very man-power intensive, if the distance between the endpoints was high. Transmission
speed of the megaphone was relatively high - the speed of sound or, 1000 km/h (600 mph) but,
the intrinsic error rate of the megaphone is also high and the amount of data transmitted at
once (or, the bandwidth of the megaphone-media) was only about 30 bit-km/sec.
Train turned out to be another relatively good transmission media, and not the least because
in addition to the very high data transmission capacity, it could also carry nearly any kind
of metadata (food, people, tools etc.) with it. It is impossible to give any unambiguous
transmission speed for the train transmission-media, since it has changed a lot due to
development and, is dependent on many external factors. The amount of data a single train can
carry is practically infinite, the amount of repeaters is virtually zero, in addition to
which, train is intrinsically equally error-free transmission media as the carrier pigeon.
As a transmission media, however, telegraph was - and still is - unequivocally the biggest
breakthrough of all times - all concurrent transmission medias and those in foreseeable
future are, and will (at a very high probability), be based on it.
Telephone was a rather logical next step after the telegraph. The two have many
similarities, including low intrinsic error rate and low bandwidth (for speech, data transfer
rates are considerably higher). Although the first telephone message ever was sent as early
as 1876 (7 words, from one room to another) and, by 1890, many cities had primitive telephone
systems, the first trans-Atlantic phonecable wasn't installed until in 1959. The first
official trans-Atlantic message (90 words) took 67 minutes to cross the ocean. As of now,
telephone is, by far, the most popular transmission media used.
The first trans-Atlantic wireless (radio) transmission was made in 1901; the letter "S" was
sent in Morse code between the USA and UK. At first, radio was a very expensive transmission
media to use, its quality was very poor and the availability of radio links was very low. In
short, radio was a very poor transmission media for critical data in its first years. It took
another 10 years to establish worldwide wireless telegraph links. By 1920, all major countries
had a small number of High Frequency radio stations for long-distance telephony - an
estimated 100 such stations worldwide.
In 1956 more phonecables were installed across the Atlantic, which added the capacity to 36
simultaneous telephone channels between Europe and North-America. This was such an increase it
was estimated to be sufficient for at least the next 15 years. Thus, the expensive and
unreliable radio links were closed. Only a few months later, however, the radio links had to
be reopened due to high demand. This, in part, triggered and encouraged the development of
a reliable wireless transmission media. A demand, that was met in 1965, as the first
commercial geostationary communications satellite Intelsat 1 (Early Bird), with 240 phone
circuits, was launched. Some subsequent satellites include Intelsat V (1980, 12500 phone
circuits) and, Intelsat VI (1989, 33000 phone circuits).
The first trans-Atlantic fiber optic was laid in 1988. It was called TAT-8, and it carried
40000 telephone circuits. Some subsequent fibre optic cables include TAT-9 (1992, 80000
telephone circuits) and TAT-12 (1996, 300000 telephone circuits). Currently, there are 10 such
cables in service and, another 10 under construction or planned.
The main differences between telecommunications (referring mainly to voice transmission)
and data networking (referring mainly to data transmission) are that telecommunication medias
are mainly circuit switched and the industry conservative, while data networking medias
are mainly packet switched and the industry dynamic.
There is a strong - and accelerating - trend for the traditional telecommunications services
to be provided using data networking technologies. There is also a strong - and accelerating -
trend for the data networking services to provide the same quality of service as the
traditional telecommunications services.
Conclusion: the two industries are consolidating. According to some predictions, this
consolidation will be complete, and the industries indistinguishable by the year 2010 (prediction made by the course lecturer Rob Parker CERN-IT).
This text is a part of a course-study in telecommunications technology.