CHAPTER 4
Type 4606 Features and Functions
49
B and C are both adjusted via the joints on the handset positioner assembly and, in contrast
to A, allow handset motion in only one plane at a time. Adjusting B rotates the handset
about an axis perpendicular to the normal of the ear-cap plane and the line of intersection of the
handset symmetry plane with the ear-cap plane. (This axis is also referred to as the z
e
-axis of
the handset – see further details in section 4.3.5.) The C rotates the handset about the line of
intersection of the handset symmetry plane with the ear-cap plane (also referred to as the y
e
-
axis).
4.3 Handset Positioner Table and Standardised
Measurements
This table (see Fig.4.11) has been developed to provide a convenient means of noting down all
measurement parameters to make repeatable measurements and to set up Type 4606 for
standardised measurements according to ITU-T Rec. P.64. The table provides fields for all the
parameters with graduated scales on them. The points at which readings should be taken are
indicated by arrows on the diagrams in the table.
4.3.1 Centering Fork
The front and rear labels relate to the centering fork placed closest to the front support foot and
rear support foot, respectively. The offset label relates to the scale on the crosspiece of the
centering fork which should be read off at the point where the crosspiece passes through the
yoke (see Fig.4.3) as shown in the Handset Positioner Table in Fig.4.11. Five sockets are
provided for mounting the centering forks and the rear support foot. These sockets are
numbered 1 –5 with socket 1 closest to the front support foot.
4.3.2 Support Foot
Front and rear share the same definitions as the centering forks along with socket position.
However, the front support foot is fixed and cannot be placed in other sockets. The height is
read off the graduated shaft of the support foot at the point where the shaft emerges from the
cradle bar. The foot on the end of the support foot in which the spikes are mounted slides from
left to right on a ratcheted guide. The foot has markings running from –5 to +5, the offset
position of the foot can be read from the number above the pointer at the centre of the guide.
The spikes can be placed in holes on the foot. The holes correspond to even numbers on the
foot markings. The type and position of the spike is noted –4S; 4S representing two short
spikes positioned in the –4 and 4 positions respectively. For long spikes L should be used to
replace S in the label.
4.3.3 End Stop
The end stop values are read from where the graduated shaft emerges from the sleeve that
forms its guide.
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