Method for interpreting dialled digits of a dialling sequence transmitted by a dialling means to a radio transceiver

A method for interpreting digits of a sequence transmitted to a radio transceiver receives at least first, second and third digits of a sequence having at least first and second intervals respectively between the digits, waits for a new digit after receiving the third digit for a waiting time, interprets the digits at an end of the waiting time, and thereafter gives a command for a radio transceiver to transmit the digits. The waiting time is determined during the sequence from at least one characteristic of each of the intervals.

The invention relates to a method for interpreting dialled digits of a 
dialling sequence transmitted by a dialling means to a radio transceiver, 
said method comprising receiving dialled digits of a dialling sequence, 
dialled by a digit dialling means, sign dialling means or the like, and 
waiting for a possible new dialled digit after the last received dialled 
digit for a specific waiting time before all dialled digits of the 
dialling sequence are interpreted as received and before the method gives 
a transmission command to a radio transceiver which will set up the radio 
connection on the basis of the dialling sequence. 
The present method can be used for several different applications. 
Basically, the present method has been developed for use in connection 
with teleadapters. A teleadapter is an adapter provided between a terminal 
equipment and a radio transceiver for adapting the user interface and 
electric interface of the radio transceiver to the properties of a 
two-wire subscriber connection in a fixed telephone network. In order to 
be able to perform such adaption, the teleadapter comprises interface 
circuits, which for instance generate a dialling tone towards the terminal 
equipment, generate a ringing voltage, indicate whether the terminal 
equipment is busy, and adjust the levels of audio signals. These interface 
circuits constitute means for connecting a terminal equipment and a radio 
transceiver to each other. With the radio transceiver, the teleadapter 
thus allows a call to be placed through a connection on a radio path by a 
normal terminal equipment of a fixed network, such as a DTMF (Dual-Tone 
Multi-Frequency) or a pulse dialled telephone, telefax or modem. The 
adapter can be used, for example, to allow a terminal equipment to provide 
services offered by a two-wire connection for buildings where there are no 
fixed telephones on account of its location, because it is under 
construction, owing to a natural catastrophe, or for some other reason. 
The radio transceiver may consist of the radio unit of a conventional 
cellular phone. The most essential advantage of the use of a teleadapter 
is that, with a radio transceiver, it can replace a missing connection of 
a fixed network with a radio path connection. The need to replace a 
connection of a fixed network is particularly pressing on an area in which 
it is not financially profitable or otherwise possible, for one reason or 
another, to build or expand a fixed network. The user does not notice any 
difference regardless of whether he uses a fixed telephone network or a 
solution implemented by a radio transceiver. 
A teleadapter can also be used for connecting a normal cellular phone to a 
modem located in, for example, a portable microcomputer: the teleadapter 
allows data to be transmitted through a conventional cellular phone 
completely independently of the fixed telephone network. 
As regards the teleadapter and the method for interpreting dialled digits 
of a dialling sequence transmitted by a dialling means to a radio 
transceiver, the problem is the interpretation of the last digit of the 
dialling sequence, because only the person who performs the dialling knows 
when he entered the last digit of the sequence. Even this person does not 
necessarily know when the last digit was dialled, since the dialling 
sequence may be entered from an intercom dialling memory location 
contained in the terminal equipment. It is important to detect the last 
digit of the dialling sequence, as, in order to avoid a time delay, a 
telephone message consisting of a dialling sequence should be transmitted 
over a bus to the radio transceiver as soon as possible once the entire 
dialling sequence, i.e. all the dialled digits, has been entered. 
The problem described above can be avoided by entering a special character 
after the last digit of the dialling sequence. The teleadapter interprets 
this special character as a transmission command by which the telephone 
message consisting of the dialling sequence is sent through the bus to the 
radio transceiver for further transmission. This special character is 
usually #. However, it is not desirable to use an extra end mark of this 
kind, as an average user assumes that call establishment can succeed 
merely by dialling a sequence of digits without the user having to enter a 
special character at the end of the dialling sequence. 
A known method developed to solve the above-mentioned problem utilizes a 
waiting time of constant length. The method awaits the dialling of a 
possible following digit for this waiting time before the method itself 
gives the transmission command to the radio transceiver which will set up 
the radio connection on the basis of the dialling sequence. In a known 
teleadapter and a method associated with it, the waiting time of constant 
length is 5 seconds. Nevertheless, a method wherein a waiting time of 
constant length is utilized is extremely inflexible, and it does not take 
differences between users or dialling sequences into account in any way. 
In the case of a sequence with six digits, for example, a person A may be 
capable of dialling all the digits at intervals of one second, for 
example, whereas another person B may perform the dialling so that the 
time interval between the dialling of the different digits may vary from 1 
to 7 seconds. The reason for this may be that the number is familiar to 
person A and/or he is able to dial all the digits in succession without 
having to check the number from the telephone directory in between. The 
number may be completely unfamiliar to person B and/or he may have to 
check the number from the telephone directory in the middle of dialling 
the digit sequence. Person B may also differ from person A in his age, 
health or perception. In the case of person A, the waiting time of 
constant length, used in the known method, is clearly too long, since the 
transmission command is not given until after 5 seconds. In the case of 
person B, the waiting time of constant length, used in the known method, 
is clearly too short, as the transmission command is already given after 5 
seconds; this is too soon, as another digit would still have been added to 
the dialling sequence 7 seconds after the preceding digit. Thus, in the 
case of person B, the call establishment would not have succeeded. 
The method utilizing a waiting time of constant length has yet another 
significant drawback, which becomes apparent when the digit sequence is 
dialled from an intercom dialling memory location of a terminal equipment. 
When a digit sequence is dialled from an intercom dialling memory 
location, the time intervals between the dialled digits of the sequence 
are obviously short and of equal length. The known method is not able to 
detect this, and therefore even in the case of digits dialled 
automatically, e.g. from an intercom dialling memory location, the method 
must wait until the waiting time of constant length, i.e. 5 seconds, has 
come to an end before the telephone message consisting of the dialling 
sequence can be transmitted to the radio transceiver. 
The teleadapter described above is not the only application with problems 
in the detection of the last digit of a dialling sequence and in the 
generation of a transmission command. This problem is also associated with 
cellular phones, as even with complete cellular phones it is necessary to 
press a transmission key after the last digit of a dialling sequence, 
whereafter the telephone message according to the dialling sequence is 
sent to the radio transceiver of the cellular phone, and a call is set up. 
As stated above in connection with a separate teleadapter, it is not 
desirable to use such an end mark; it would be easier for the user if a 
call could be set up merely by dialling a sequence of digits without the 
user having to enter any special character at the end of the dialling 
sequence. Even cellular phones require a teleadapter of some kind to adapt 
the radio transceiver of the cellular phone to the dialling means, 
earpiece and microphone. In such an application, the teleadapter would not 
necessarily be a separate element as stated above, but it would preferably 
be an integral part of the cellular phone. As regards the present 
invention, it must be pointed out that the term teleadapter is to be 
understood widely so that its function and the elements included in it may 
vary depending on the application in which it is used. In the 
last-mentioned application, the teleadapter does not have to comprise 
means for generating a ringing voltage or a dialling tone, as the cellular 
phone is not connected to a two-wire interface. 
Another known method is number analysis. In number analysis, the dialling 
sequence, or the telephone number, dialled by the user is analyzed; if it 
is detected that the dialled number is, for instance, an emergency number, 
the number is transmitted immediately. A disadvantage of this method is, 
for example, that different countries have different emergency numbers and 
that it is applicable only with certain numbers. 
The object of the present invention is to provide a new type of method by 
which the problems associated with the known solutions can be avoided. 
This is achieved with the method of the invention, which is characterized 
in that the waiting time differs from a constant time, but is determined 
during the dialling sequence, that the method comprises determining one or 
more characteristics describing the intervals between the digits of the 
dialling sequence dialled so far, that the waiting time is determined on 
the basis of said one or more characteristics, and that said one or more 
characteristics and the waiting time are determined several times during 
the same dialling sequence as the dialling of the digits proceeds. 
The method of the invention has several advantages. In the method of the 
invention, the waiting time is dependent on how a user performs the 
dialling of a digit sequence. If the user dials the digits of the sequence 
in such a way that the time intervals between the dialled digits are 
short, the waiting time is short, too; the transmission command relating 
to the telephone message consisting of the dialling sequence can be given 
sooner, and thus also the call establishment can be started after only a 
short while. Correspondingly, in the case of a user who dials the digits 
of a dialling sequence at long intervals, the waiting time is extended to 
prevent the dialling from being interrupted by a transmission command 
transmitted too soon. The solution of the invention allows the waiting 
time to be adapted to different people and different dialling sequences. 
Certain types of numbers are obviously easier to dial than others. It is 
also obvious that a familiar number is dialled at shorter and more even 
intervals than any unfamiliar number. A special advantage of the present 
method is that it allows dialling sequences entered by automatic dialling 
to be transmitted more rapidly. Technically, the present method is easy to 
implement. The devices needed for carrying out the method can be provided 
as part of a separate teleadapter, or they can be integrated into a 
cellular phone. The devices for carrying out the method of the invention 
have the same advantages as the method. The new method is a rapid method 
of analysis.

At first, the use and the teleadapter or the like of the first embodiment 
of the invention will be described with reference to FIGS. 1 to 3. FIG. 1 
shows a terminal equipment 1, a teleadapter 2, and a radio transceiver 3, 
which may be a conventional cellular phone without a user equipment 
connected to a user interface. The terminal equipment 1, in turn, may be a 
DTMF (Dual-Tone Multi-Frequency) or a pulse dialled telephone, telefax or 
modem. In the example of FIG. 1, the terminal equipment 1 is a dual-tone 
telephone device comprising a dialling means 1a, such as a set of keys 1a, 
and a handset 1b. The terminal equipment 1 is connected to the teleadapter 
over a two-wire connection 4. The radio transceiver 3 is connected to the 
teleadapter 2 over a transmission link 5, such as a bus. The transmission 
link 5 comprises a data bus and audio lines. The transmission link 5 may 
be either serial or parallel. In practice, the structures illustrated in 
FIG. 1 may be located so that the terminal equipment 1 is connected to the 
two-wire interface 6 of the teleadapter 2, and said two-wire interface 6, 
in turn, is connected to the radio transceiver 3 located in the same 
space. The radio transceiver comprises a radio transceiver unit 3a, a 
control unit 3b and an antenna 3c. 
The function of the teleadapter shown in FIG. 1 is to adapt the user 
interface and electric interface of the radio transceiver 3 to the 
properties of a two-wire subscriber connection in a fixed telephone 
network; in other words, the aim is to adapt a normal terminal equipment 1 
and a radio transceiver 3 which replaces a connection of the fixed network 
to each other. 
FIGS. 2 and 3 are diagrams illustrating the internal operation of the 
teleadapter. The teleadapter 2 comprises a two-wire interface 6 or a 
corresponding interface to a terminal equipment 1, and an interface 7 to a 
radio transceiver 3. The terminal equipment 1 is thus connected to the 
interface 6 by a two-wire connection 4, and the radio transceiver 3 is 
connected to the interface 7 by a bus cable 5 or another transmission 
line. 
The actual parts of the teleadapter 2 can be enumerated as follows: 
HOOK detector block 11, which identifies whether the terminal equipment 1 
is busy or idle, i.e. whether the handset 1b of the terminal equipment is 
off the hook or not. The block 11 may also be used for identifying the 
dialling sequence entered by a pulse-dialled terminal equipment. 
A ringing voltage generator 12, which generates a ringing voltage to the 
terminal equipment 1 when the terminal equipment 1 is about to receive a 
call through the radio transceiver 3 and the teleadapter 2. 
A line converter 13, which connects the outgoing and incoming audiosignal 
to the same line. The line converter 13 is a 2-4 converter, which allows a 
bidirectional audio signal to propagate along a two-wire connection 4. 
A line voltage generator 14, which generates a line voltage, e.g. a DC 
voltage of 48 V or 60 V. The line voltage is needed to generate a line 
current by which it is possible to provide a closed connection loop 
corresponding to the busy state of the telephone, i.e. to the OFF-HOOK 
state when the handset is lifted. 
A voltage regulation block 15. A voltage of 12 V is obtained from a battery 
or some other power source. The voltage of 12 V is supplied to the block 
15, which generates from this voltage a logic voltage of 5 V, required by 
a control unit 18, such as a central processing unit (CPU), included in 
the teleadapter. 
An audio level adjustment block 16. First, the block 16 adapts to the radio 
transceiver 3 the audio signals received from the terminal equipment 1 
through the telephone line, i.e. the two-wire connection, and the two-wire 
interface 6. Second, the block 16 adapts the audio signals received from 
the radio transceiver 3 to the terminal equipment 1. The block 16 adjusts 
the levels of the audio signals. This kind of adjustment is needed, 
because the models of different manufacturers and even different models of 
the same manufacturer differ from each other as to the level of the audio 
signal that allows the most efficient use of the radio channels. 
Transmission link adapter block 17, which consists of a bus adapter if the 
transmission link 5 from the teleadapter 2 to the radio transceiver 3 is a 
bus. The block 17 transfers message communications from the teleadapter 2 
through the interface 7 to the radio transceiver 3. The block 17 converts 
the serial data received from the TX output of the control unit 18 into a 
suitable form, and sends the data further to the radio transceiver 3 
through the transmission link 5. Correspondingly in the opposite 
direction, the block 17 converts data transmitted to it from the radio 
transceiver 3 through the transmission link 5 and the interface 7 into 
serial form, whereafter the data can be supplied to the RX input of the 
control unit 18. 
A control block 18, which controls the operation of the teleadapter 2. The 
block 18 comprises a program memory 18a, a scratch pad storage 18b, and a 
self-control unit 18c. The most significant part for the present invention 
is block 18d, which is the block for determining the waiting time T. The 
control block 18 generates the main part of the control operations needed 
by the teleadapter 2. An example of the control operations given by the 
control block 18 is the CALL CONTROL output, which instructs the block 12 
to generate a ringing voltage, when a call is coming from the radio 
transceiver 3. Another example of the control operations given by the 
block 18 is the output indicated as 425 Hz. This output generates an 
idle/busy tone to the audio line 4 when the handset is lifted off the hook 
for placing/answering a call. 
A DTMF receiver 19. The block 19 receives a dialling sequence, or digit 
sequence, from the dialling means 1a, i.e. digit dialling means 1b such as 
a set of keys, of a terminal equipment 1. The block 19 decodes the DTMF 
dialling sequence, and converts it into a form compatible with the control 
unit 18. 
A line impedance setting block 20, which is needed, as terminal equipments 
in different countries have different impedance responses. The block 20 
allows the impedance level to be adjusted specifically for each country. 
In FIG. 2, the thicker line 21 defines galvanic isolation, which is used to 
prevent disturbance voltages from propagating from the terminal equipment 
to the radio transceiver and vice versa. The teleadapter can also be 
implemented without galvanic isolation. 
The present invention actually relates to a method for interpreting dialled 
digits of a dialling sequence transmitted by a dialling means 1a, such as 
the set of keys of a terminal equipment 1, to the radio transceiver 3. A 
dialling sequence entered by a user is illustrated in FIG. 5 by the 
uppermost time diagram 22, which represents a DTMF pulse line 22 in which 
each pulse 22a-22f represents a single digit of the dialling sequence. The 
dialling sequence 22 shown in FIG. 5 comprises thus six digits 22a-22f 
entered by a user by the set of keys la of a terminal equipment 1. 
The method comprises receiving dialled digits 22a-22f included in a 
dialling sequence 22 and entered by a digit dialling means la one at a 
time. After the last received dialled digit, a possible new dialled digit 
is awaited for a specific waiting time T until all dialled digits 22a-22f 
are interpreted as received, and until a transmission command is given to 
the radio transceiver 3 which will set up the radio connection on the 
basis of the dialling sequence 22. The waiting time is determined in the 
control block 18, more specifically its block 18d. If the terminal 
equipment is a DTMF terminal equipment, the dialled digits 22a-22f thus 
propagate one at a time from the set of keys 1a of the terminal equipment 
1 to the two-wire interface 6, to block 12 and block 13, to signal path 
13a and signal path 13b, and further to the DTMF receiver 19, from which 
each single dialled digit, e.g. digit 22a, propagates to the DTMF data 
input of the control unit 18, and further to the block 18d where the 
waiting time T is determined. 
In the method according to the invention, the waiting time T differs from a 
constant time, i.e. is not of constant length, but is determined during 
the dialling sequence 22. Block 18d determines one or more characteristics 
illustrating the intervals between those digits of the dialling sequence 
22 which have been dialled so far. The waiting time T is determined on the 
basis of said one or more characteristics several times during the same 
dialling sequence 22 as the dialling of the digits 22a-22f of the sequence 
22 proceeds. 
In FIG. 5, the time intervals between the dialled digits 22a-22b, 22b-22c, 
22c-22d, 22d-22e and 22e-22f of the dialling sequence are indicated by 
references t1 to t5. A dialling sequence 22 of six digits thus comprises 
five intervals t1-t5 between the digits 22a-22f. 
According to a preferred embodiment of the method, said one or more 
characteristics used for determining the waiting time T are obtained by 
defining the number N of the digits dialled so far, and the intervals 
between them. If a user has dialled only the first digit, the number N of 
dialled digits is 1, and the waiting time T has a calculated value or an 
initial value determined in some other way. Correspondingly, if the user 
has dialled, for example, the first four digits 22a-22d, the number N of 
dialled digits is 4, and the waiting time is determined on the basis of 
one or more characteristics determined on the basis of the three intervals 
t1, t2 and t3 between the first four digits. 
According to a preferred embodiment, the characteristic used for 
determining the waiting time T is the average X of the time intervals 
between the digits dialled so far, or a corresponding characteristic. For 
determining the waiting time T, the method utilizes a factor f(X) which is 
dependent on the average of the intervals between the dialled digits, or a 
corresponding characteristic X. In the simplest solution, the factor f(X) 
may be directly of the form f(X)=X, but in the most preferred embodiment, 
the function f(X) allows a suitable range of variation for the waiting 
time. 
In a preferred embodiment, the characteristic used for determining the 
waiting time T is the standard deviation S of the intervals between the 
digits dialled so far, or a corresponding deviation characteristic. For 
determining the waiting time T, the method utilizes a factor f(S) which is 
dependent on the standard deviation of the intervals between the dialled 
digits, or a corresponding deviation characteristic. 
Most preferably, both the average X and the standard deviation S are used 
for determining the waiting time T. In this case, T=f(X, S)=K*f(X)*f(S), 
wherein K is a constant (i.e., the waiting time is directly proportional 
to the factor). Factor f(X), dependent on the average X, and factor f(S), 
dependent on the standard deviation S, allow a different value to be 
determined for the waiting time T in different situations. What is meant 
by different situations is that the intervals between the dialled digits 
may be short in some dialling sequences and long in others, and the 
standard deviation of the intervals between the dialled digits may be 
small in some dialling sequences and great in others. 
In the method of the invention, if a new dialled digit 22d is received 
after, for example, the third dialled digit 22c before the waiting time 
has come to an end, the interval between the new dialled digit and the 
preceding dialled digit is taken into account when the waiting time is 
determined again. The method of the invention thus monitors the dialling 
continuously and adapts itself continuously depending on how the user or 
automatic dialling performs the dialling. 
In FIGS. 4 and 5, the waiting time T is the waiting time calculated after 
the last dialled digit 22f. However, the method comprises calculating a 
new waiting time after each dialled digit, taking into account the 
intervals between the digits dialled so far; a characteristic is 
calculated on the basis of these intervals, and the waiting time T is 
determined on the basis of this characteristic. In the case of a dialling 
sequence with six digits, the waiting time T is thus determined six times. 
However, in a preferred embodiment, the calculation of 
characteristics/determination of the waiting time is started only after 
two digits, as it is not possible to calculate the first average until 
then. The waiting time T is therefore determined five times in the case of 
a telephone number with six digits. 
The number of times the waiting time is determined is thus the same as the 
number of the dialled digits 22a-22f of the dialling sequence 22. 
The object of the method of the invention is to adapt the waiting time T 
according to how the digits 22a-22f are dialled. Therefore, when the 
average X of the intervals t1 . . . between the dialled digits, or a 
corresponding characteristic, grows, the waiting time T is extended. 
Correspondingly, when the standard deviation S of the intervals t1 . . . 
between the dialled digits, or a corresponding characteristic, grows, the 
waiting time T is extended. 
In a preferred embodiment, the intervals t1 t2 between the digits dialled 
at the beginning of the dialling sequence, e.g. between the first three 
dialled digits 22a, 22b, 22c, are emphasized less than the intervals t3, 
t4, t5 between the digits 22c, 22d, 22e, 22f dialled later. This procedure 
is required, as it can be assumed that the area code (three first digits) 
occurring at the beginning of the dialling sequence can be dialled more 
rapidly and at more even intervals than the actual subscriber number. The 
digits dialled at the beginning of the sequence should therefore be 
considered less significant in order to prevent the determination of the 
waiting time T from being distorted. 
In a preferred embodiment, the method comprises determining the waiting 
time T in such a way that the determination is free of the use of a fixed 
minimum waiting time, i.e. no fixed minimum waiting time is used. 
Likewise, no fixed maximum waiting time is used in the determination of 
the waiting time. According to this embodiment, the waiting time T is 
determined in such a manner that the method avoids any problems which 
might occur if fixed time limits were used. 
The following is a description of the use of the method for interpreting a 
dialling sequence 22 according to FIG. 5. A user dials the first digit 22a 
by a dialling means 1a of a terminal equipment 1, the dialled digit is 
received at block 9, and further at a control unit 18, and block 18d 
contained in it, i.e. the block for determining the waiting time for the 
following digit. As this is the first dialled digit, no time interval 
between digits exists yet. At any rate, the function T=K*f(X)*f(S) gives a 
certain value T1, which is set as the waiting time for the following 
dialled digit 22b. The interval t1 is shorter than the waiting time T1, 
wherefore the following dialled digit 22b is received (dialled by the 
user) before the waiting time T1 comes to an end. After receiving dialled 
digit 22b, block 18d detects that the user has now dialled two digits. 
Then block 18d determines the interval t1 between the first two digits 
22a, 22b. As no other intervals than interval t1 can be used in the 
determination of the waiting time, the average obtained by calculation in 
block 18d is time t1 and the standard deviation is 0. On the basis of 
these characteristics, block 18d determines a new waiting time T2 for the 
following dialled digit 22c. The interval t2 is shorter than the waiting 
time T2, wherefore the following dialled digit 22c is received (dialled by 
the user) before the waiting time T2 comes to an end. 
After receiving dialled digit 22c, block 18d detects that the user has now 
dialled three digits. Block 18d then determines the interval t2 between 
the second and the third dialled digit 22b, 22c. As time intervals t1 and 
t2 can be used for determining the waiting time, the average X obtained by 
calculation in block 18d is the time (t1+t2)/2, and the standard deviation 
is a certain value S, which is the standard deviation of intervals t1 and 
t2. On the basis of these characteristics X and S, block 18d determines a 
new waiting time T3 for the following dialled digit 22d. The interval t3 
is shorter than the waiting time T3, wherefore the following dialled digit 
22d is received (dialled by the user) before the waiting time T3 comes to 
an end. 
After receiving dialled digit 22d, block 18d detects that the user has now 
dialled four digits. Block 18d then determines the interval t3 between the 
third and the fourth dialled digit 22c, 22d. As time intervals t1 t2 and 
t3 can be used for determining the waiting time, the average X obtained by 
calculation in block 18d is the time (t1+t2+t3)/3, and the standard 
deviation is a certain value S, which is the standard deviation of 
intervals t1 t2 and t3. On the basis of these characteristics X and S, 
block 18d determines a new waiting time T4 for the following dialled digit 
22e. The interval t4 is shorter than the waiting time T4, wherefore the 
following dialled digit 22e is received (dialled by the user) before the 
waiting time T4 comes to an end. 
After receiving dialled digit 22e, block 18d detects that the user has now 
dialled five digits. Block 18d then determines the interval t4 between the 
fourth and the fifth dialled digit 22d, 22e. As time intervals t1 t2, t3 
and t4 can be used for determining the waiting time, the average X 
obtained by calculation in block 18d is the time (t1+t2+t3+t4)/4, and the 
standard deviation is a certain value S, which is the standard deviation 
of intervals t1 t2, t3 and t4. On the basis of these characteristics X and 
S, block 18d determines a new waiting time T5 for the following dialled 
digit 22f . The interval t5 is shorter than the waiting time T5, wherefore 
the following dialled digit 22f is received (dialled by the user) before 
the waiting time T5 comes to an end. 
After receiving dialled digit 22f , block 18d detects that the user has now 
dialled six digits. Block 18d then determines the interval t5 between the 
fifth and the sixth dialled digit 22e, 22f . As time intervals t1 t2, t3, 
t4 and t5 can be used for determining the waiting time, the average X 
obtained by calculation in block 18d is the time (t1+t2+t3+t4+t5)/5, and 
the standard deviation is a certain value S, which is the standard 
deviation of intervals t1 t2, t3, t4 and t5. On the basis of these 
characteristics X and S, block 18d determines a new waiting time T for the 
following dialled digit. 
However, the user has already dialled all the digits, wherefore no further 
dialled digits are received during the waiting time T. After the waiting 
time T, the method thus interprets that the last digit of the dialling 
sequence 22 has been received. As a result of this, the method generates a 
transmission command, by which the telephone message according to the 
dialling sequence is transmitted through block 17, interface 7 and bus 5 
to the radio transceiver 3, which will then start to set up a connection 
to the telephone number indicated by the dialling sequence. 
FIG. 4 is a time diagram of a dialling sequence 23 entered by automatic 
dialling, and the corresponding waiting time TT following the last dialled 
digit. In FIG. 4, the digits of the dialling sequence are indicated by 
references 23a to 23f. The dialling sequence 23 has perfectly even 
intervals, as it is entered by automatic dialling from an intercom 
dialling memory location of a terminal equipment 1. In principle, the 
dialling sequence of FIG. 4 is interpreted in the same way as dialling 
sequence 22 above. As the average interval X between the dialled digits of 
the dialling sequence 23 is short, and the standard deviation S=0, the 
waiting time TT after the sixth dialled digit 23f is quite short, as can 
be seen from FIG. 4, and thus the transmission command can be given soon 
after the last digit 23f. 
In the embodiment illustrated in FIGS. 1 to 3, the radio transceiver 3 used 
in the method is a fixed or mobile cellular radio transceiver, and the 
dialling means 1b is contained in a terminal equipment 1 which is separate 
from the cellular radio transceiver. The separate terminal equipment 1 is 
connected to the cellular radio transceiver 3 through a teleadapter 2 or 
the like. The teleadapter 2 comprises means, such as blocks 12 to 20, for 
connecting the terminal equipment 1 and the cellular radio transceiver 3 
to each other. Whether blocks 12 to 20 are needed depends on whether the 
case concerns connection to a two-wire connection. 
FIG. 6 illustrates a second embodiment of the method according to the 
invention, integrated into a cellular phone 100. The cellular phone 100 
comprises a case 100a with a dialling means 101a, such as a set of keys, 
and a handset 200 with a microphone 200a and an earpiece 200b. In 
addition, the cellular phone 100 comprises an adapter 102, and a radio 
transceiver 103 comprising a radio transceiver unit 103a, a control unit 
103b and an antenna 103c. The adapter 102 comprises blocks 119, 118, 118d, 
116 and 117, whose operation and function correspond to those of blocks 
19, 18, 18d, 16 and 17 of the teleadapter 2 of FIG. 2, respectively. Block 
119 is a means for receiving the dialled digits of the dialling sequence, 
block 118 is a control unit, block 118d is a means for determining the 
waiting time T, block 116 is a means for adjusting audio levels, and block 
117 is a means for transmitting the telephone message formed by the 
dialling sequence to the radio transceiver 103. 
The embodiment shown in FIG. 6 is not used for connecting a radio 
transceiver to a two-wire connection, wherefore the adapter 102 does not 
have to contain all the interface circuits, or adapting means, included in 
the teleadapter 2 of FIG. 2. The embodiment of FIG. 6 does not need, for 
instance, a ringing voltage generator or a HOOK detector block. 
In the example illustrated in FIG. 6, the radio transceiver 3 used in the 
method is a radio transceiver of a fixed or a mobile cellular phone 100. 
The dialling means 101a is either contained in the cellular phone itself 
or connected to the data bus of the radio transceiver. In pay phones, for 
example, it is possible to use a dialling means connected to the data bus 
of the radio transceiver. The dialling means may be positioned in the 
handset or integrated into the case 100a. 
The cellular phone shown in FIG. 6 may be, for example, a model intended 
for use as a wireless home terminal or a model intended for use as a pay 
phone. If the functions of the handset 200, i.e. the microphone and the 
earpiece, were also integrated into the case 100a, the phone would be a 
cellular phone of hand-portable type. As regards the method of the 
invention, the embodiment shown in FIG. 6 operates in the same way as the 
embodiment shown in FIGS. 1 to 3. 
In a preferred embodiment, determination of the waiting time T is 
controlled by the same control unit 103b that is used for controlling the 
operation of the cellular phone 100. In FIG. 6, this is illustrated by 
control line 300, which connects the control unit 103b of the cellular 
phone to the control unit 118 of the adapter 102. This embodiment makes 
the arrangement more compact. 
With respect to the term cellular phone, it must be stated that a cellular 
phone can be either fixed or mobile. A fixed cellular phone remains within 
the area of one cell in a base station network. Examples of such a fixed 
cellular phone are cellular phones positioned in a building or intended 
for use as pay phones. A mobile cellular phone may roam from one cell to 
another within a base station network. An example of a mobile cellular 
phone is a normal portable cellular phone or a cellular phone positioned 
in a train. 
The function for determining the waiting time T is such that, according to 
the method of the invention, the waiting time is from 1 to 10 seconds, 
depending on how the telephone number is dialled. 
Although the invention is described above with reference to the examples 
shown in the accompanying drawings, it will be obvious that the invention 
is not limited to these examples, but can be modified in many ways within 
the inventive concept disclosed in the appended claims.