THE TELEPHONE HANDSET
Although the first telephones worked, they were uncomfortable to use. Watson
described using Bell's "gallows" telephone as like holding a packing
case in your hand. More work had to be done on the ergonomics. This was limited
in the United States by the size of the transmitters- they were so large that
they had to be mounted on (or in) large wooden wall boxes. The widely used Blake
transmitter needed a box of its own. Even the White Solid Back transmitter that
replaced it was inconveniently large for a handset.
In
spite of this, people saw the advantage of having the transmitter and receiver
combined. As early as February 3, 1880, Robert G Brown received a U.S. Patent
for an "Electric Speaking-Telephone" that was simply a handset.
(1). In his claim, he stated "I do not broadly claim the combination
in one instrument of two so arranged that when one is applied to the mouth
the other will be applied to the ear …as I am aware such subject-matter
is not new". Brown's patent was for an arrangement of the receiver
that allowed it to be adjusted to the user's head length, and a semi-pivoting
transmitter whose angle would adjust somewhat to face the user's mouth. We
have no information on who first suggested joining two instruments, but the
concept was well known to Brown. He built some of his telephones for Western
Union's Gold and Stock Exchange, for whom he worked. His invention was viewed
with an almost total lack of interest so he went to France and became a General
Engineer for Societe Generale des Telephones. They liked the handset idea
and produced their first model in 1879. It was rather sensitive to vibration,
but this helped reduce packing of the carbon granules so was not as much of
a drawback as it seemed.
Brown was preceded by two British inventors, Charles McEvoy and G E Pritchett.
Both received patents in 1877 for handsets. McEvoy described a Butterstamp
receiver with a speaking tube attached to it that reached down in front of
the user's mouth. The tube was attached to another Bell transmitter at the
telephone end.
Pritchett described a surprisingly modern-sounding handset in general terms,
but since practical hardware did not exist at the time to build it his patent
did not attract interest. (2)
This is a good time to examine the problems of handsets, as compared to the
separate transmitter / receiver.
Size: the components of the time were bulky, but good engineering
and refinement was reducing the size. Europe had the advantage of having many
inventors and companies working on the problems, but in the U.S , because
of the patent issues and the capital demands of an ever-growing telephone
system, research funds were limited. French inventor Mercadier showed that
a receiver could be scaled down to quite a small size, provided critical ratios
such as diaphragm gap to magnet assembly were maintained. This allowed Ader,
particularly, to develop a watchcase receiver that was quite efficient and
small enough to use on a handset. The Hunnings, Berliner and Edison carbon
transmitters, although rather ignored by Bell in the U.S., were developed
into practical small transmitters in Europe. Even Berthon's carbon pencil
transmitter was miniaturised to handset size.
Sidetone: this is the effect caused when sound going into the transmitter
is fed back into the receiver. It distorts the received sound, making it sound
"tinny" and less clear. The effect was usually electrical and applied
to separate transmitter/receiver telephones as well, but the tubes in early
handsets were also a major cause of acoustic feedback which also generated
sidetone. At worst the sound could then feed back into the transmitter, be
regenerated back into the receiver, and generate a howling noise that made
conversation impossible. By 1918 Western Electric had developed an anti-sidetone
circuit to remove this problem.(3)
Efficiency: Since the sound waves did not strike directly onto the
diaphragm, in spite of the cup mouthpieces used on many handsets, the output
from the transmitter was lower than the wall-mounted transmitters. Ralph Meyer
(3) notes that Kellogg used a retardation circuit in its early phones, and
this combined with the lower level of signal reduced the acoustic feedback
in Kellogg's Grabaphone. The different lengths of the users' heads could also
place the transmitter in a less-than-optimal position. Some companies like
British Insulated & Helsby experimented with variable length transmitters
(as described in Brown's patent) to overcome this.
Packing: Like the wall-mounted transmitters, handsets suffered when
the carbon granules packed down to the bottom of the transmitter. In some
cases they could fall away from the center electrode and interrupt the conversation.
The movement of the head and the pickup and replacement of the handset usually
kept the granules from packing, so this was not a major problem. Even so,
Berthon Ader issued an instruction leaflet with their telephones to show users
the best angle for the handset. In the late 1890s - early 1900s Bell Telephone
Manufacturing in Antwerp developed a small Solid Back capsule transmitter
that effectively removed the packing problem from its handsets. In spite of
this, it was not introduced into the U.S.
In 1892 L M Ericssons in Sweden released their Model AC110 "Skeletal"
or "Eiffel Tower", featuring a well-designed and efficient handset.
A similar handset was released by the Bell Telephone Manufacturing Company
of Antwerp on their "Eiffel Tower" phone some years later, and handset
telephones became a familiar sight in Europe. During World War 1, U.S. servicemen
saw these telephones and christened them "French" phones, a name
which is still inaccurately applied to handset phones by eBay sellers today.
Now let's look at some of the significant early handsets.
Berthon Ader
These were built somewhat similar to Brown's pattern, with a large flat steel
handle, but without using the handle as a magnet. They did not follow Brown's
"pivoting" transmitter.
The large transmitter was a three-carbon-pencil model. The right angle shape
of the handset meant the sound waves from the voice worked directly onto the
diaphragm. The receiver was a conventional Ader watchcase receiver, and the
whole handset was fairly rugged and efficient.
L M Ericsson
The success of Ericsson's 1890 handset depended on the reliable transmitter.
This gave a compact well-balanced handset that worked particularly well, and
had a style about it that many early handsets lacked. Poole (4) described
the transmitter in detail. His description is available on this website
Ericsson broke the metal tube into two short pieces joined into an ebonite
handle. This reduced acoustic feedback and sidetone usefully. A pushbutton fitted
to some handsets cut out the transmitter on noisy or faint lines.
There were complaints in Britain that the transmitter was relatively insensitive,
but this seems hard to justify as it was quite adequate on lines of over 30
miles in Australia. Possibly to overcome the problem, an improved transmitter
was introduced progressively in models built after the First World War.
Kellogg Monophone
The Monophone, by Kellogg and many others, was mostly only seen in Europe.
It was a response to outbreaks of tuberculosis, a respiratory disease that was
often fatal. The monophone design allowed the speaking trumpet to be sterlilised
safely. Similar styles of handset were built using Berliner transmitters, and
they were particularly popular in France.
Acoustic feedback should have been a major problem with such a design In fact
the Phonopore company did use such a device to generate a feedback howl for
signaling. In use, however, this does not seem to have been a problem as the
style was quite widely used. Partly this may be due to a French modification
that cut small slots into the trumpet near its base. This reduced the pressure
on the diaphragm and cut acoustic feedback.
Bell Telephone Manufacturing Company, Antwerp
BTMC had access to much new technology that never made it back to the United
States, and so were able to produce some technically advanced phones. Their
handset was made in polished aluminium, a new metal for telephones. Aluminium
was less resonant than the usual brass or steel, and feedback does not seem
to have been a problem. The handset grip was available in a plain style not
unlike Ericsson's, or an ornate floral-patterned "deluxe" :style.
It was issued in a number of styles over the years, but its strong point
was that it had one of the first capsule transmitters. This proved less susceptible
to sidetone and feedback. It was based on an improved Hunnings design, the
White Solid Back.
Western Electric
In the United States the handset did not go unnoticed. WE engineers had experimented
with the style since the 1890s, and some models went into very limited production.
They seem to have made every mistake that their European counterparts had
already worked around - all-metal cases, one-piece tubes that maximized feedback
and sidetone, and large bulky transmitters. The disadvantages of sidetone
and acoustic feedback soon became apparent and production was eventually stopped
on the instruction of J J Carty, the Chief Engineer. Although an anti-sidetone
circuit was designed as early as 1918, handsets did not go back into production
until the first E1 bakelite models appeared in 1927.(3). It is possible that
this handset was based on a model used by the French PTT as early as 1924.
The No. 1 handset at left was patented in 1903. The No. 2 handset shown in
the center featured a built in switch attached to the suspension ring at the
top. Taking the handset "off hook" released the switch, which was
probably a better arrangement than other companies' "press to talk"
switches.
Kellogg Grabaphone
When Western Electric did not proceed with handsets in the U.S., it was left
to their competitor Kellogg to produce the first commercial production handset
phone in 1905. They called their earliest handset the "microtelephone",
but after redesigning the handset for mass production it was renamed the Grabaphone,
and fitted it to a number of models.
Kellogg was selling telephone parts into Europe through agents, and were made
aware of the handsets in use. Their first handset was based initially on Ericsson
parts but was soon redesigned and improved into a simpler, more rugged model.
It, too, disappeared when bakelite handsets finally appeared.
Western Electric E1
This was WE's first bakelite handset, designed to house their new No. 395 transmitter.
The receiver was the usual efficient watchcase design. They went to a lot of
trouble over the handset, measuring average head sizes to get the best handset
length. The anti-sidetone circuit designed to go with it was not yet ready but
the bakelite handset moulding proved excellent at reducing acoustic feedback
(and so sidetone).
The rather ungainly transmitter was actually an advantage as it put the diaphragm
of the transmitter closer to the user's mouth for a better signal.
M Ericsson 1001
In 1932 L M Ericssons started production of their first bakelite phone, the
DBH1001. Initially it was made by their Norwegian subsidiary, Elektrisk Bureau,
since it had been substantially designed by Johann Christian Bierknes, one
of EB's engineers, and Norwegian designer Jean Heiberg. It was a little more
angular than the Western Electric E1 and used a more compact transmitter capsule.
It became Ericssons' standard handset for many years and was only seriously
redesigned after the Second World War.
Siemens No. 162 Telephone
In 1924 the British Post Office and Siemens reexamined the handset as a basis
for new telephones to replace their standard candlestick-style desk phones.
Siemens developed a new telephone, christened the Neophone, in bakelite with
a new handset. The transmitter and receiver were reliable capsules designed
for long life and fast changeover. Its only disadvantage was a triangular cross-section
grip, which some found uncomfortable. It was successful, however, and customers
became used to the convenience of handset telephones. It was widely exported
and became the standard telephone for most British-influenced countries.
The 162 and its 1937 replacement, the 300 series, lasted successfully until
the 1950s. The handset, now listed as the No. 164, was then replaced with a
smoother, more rounded Ericsson handset which finally did away with the scooped
mouthpiece and the strengthening ridge along the top of the handle.
References
1. United States Patent and Trademark Office, Patent No 224,138
2. Povey P J and Earl R A J "Vintage Telephones of the World"
3. Meyer Ralph O. "Old Time Telephones - Technology Restoration and
Repair" TAB Books 1995
4. Poole J. "The Practical Telephone Handbook" 5th Edition
1912
5. London Times of 8th May 1929: "Hand Combination Telephones - An Improved
Type" from "British Telephones website
