Call routing system for a wireless data device

A call routing system includes an authorization and call routing equipment (ACRE) 117, a cordless base station 115 connected by a wireline network 111 having caller identification. The cordless base station 115 initiates a call to the ACRE 117, which receives the cordless base station's 115 telephone number. The ACRE 117 then uses the telephone number for routing subsequent telephone calls to the cordless base station 115. The cordless base station 115 can receive and store caller indentification information and transmit this information to a radiotelephone 101.

FIELD OF THE INVENTION 
The present invention relates generally to portable telephones, and more 
particularly to an improved portable telephone that operates in both 
cordless and cellular telephone systems. 
BACKGROUND OF THE INVENTION 
A cordless telephone system typically includes a portable cordless handset 
and a cordless base station connected to a telephone company phone system 
(TELCO) by telephone landlines. The cordless base station has an assigned 
landline telephone number that allows the user to place and receive calls 
using the cordless portable handset within a limited range of the cordless 
base station, such as in a home. However, due to their limited range, the 
cordless portable handset provides the user with relatively local 
radiotelephone communication. 
Radiotelephone communication outside the range of the cordless telephone 
system may also be provided to the user via a cellular telephone system. A 
cellular telephone system typically includes cellular subscriber units 
(mobile or portable) and cellular base stations connected to the TELCO via 
one or more cellular switching networks. Each cellular subscriber unit has 
an assigned cellular telephone number that allows the user to place and 
receive calls within a widespread range of the cellular base stations, 
such as throughout a metropolitan area. However, the cost of using the 
cellular telephone service is much greater than the cordless telephone 
service. 
A problem exists for the user that frequently relocates between the 
cordless and cellular telephone systems. An incoming call routed to the 
system where the user is not located may be missed. In the prior art, 
landline and cellular telephone companies have provided a solution to this 
problem with features known as No Answer Transfer or Call Forwarding or 
Three Way Calling. No Answer Transfer enables the user to program the 
system to route an incoming call from the cellular telephone system to the 
cordless telephone system or visa versa when the user's telephone that was 
called is not turned on, not answered, or out of range of the base 
station. Thus, the user may receive an incoming call placed to either the 
cordless or cellular telephone system. 
Some problems exist with the No Answer Transfer feature. The user must 
manually program the system each time there is a need to activate or 
deactivate the No Answer Transfer feature. Manually programming the system 
is a cumbersome task for the user and forgetfulness of the user may result 
in missed or improperly routed incoming calls. The user must also purchase 
and operate unique radiotelephone equipment for both the cordless and 
cellular telephone systems resulting in increased cost and inconvenience 
to the user. 
Accordingly, there is a need for a radiotelephone system that enables a 
user to receive incoming calls via both a cordless and cellular telephone 
system without the imposing inconvenience and expense on the user.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
A generalized block diagram of an application of the present invention is 
shown in FIG. 1. A portable cellular cordless (PCC) radiotelephone device 
101 is shown having the ability to communicate with a conventional 
cellular radiotelephone system 103, which has a plurality of cellular base 
stations 105, 107 located at geographically separate locations but 
arranged to provide radiotelephone coverage over a wide geographic area. 
The cellular base stations are coupled to a control terminal 109 which 
provides coordination among the plurality of cellular base stations, 
including handoff of user cellular mobile and portable equipment, and 
provides call switching and interconnect to the public switched telephone 
network (identified hereinafter as "TELCO") 111. 
The PCC 101 further has the capacity to communicate with a microcellular 
base station 113, which is a cellular adjunct cell having lower power and 
limited capabilities but providing radiotelephone service to distinct 
areas such as shopping malls, airports, etc. The microcellular base 
station 113 is coupled to the TELCO 111 landline telephone system so that 
calls can be placed to the TELCO. 
The PCC 101 further has the capability to communicate with and place 
radiotelephone calls via a cordless base station 115, which provides 
private telephone line interconnection to the TELCO 111 for the user of 
the PCC 101. The cordless communication system uses an authorization and 
call routing equipment (ACRE) 117 to provide call routing information to a 
telephone switching system. Thus, the switching system automatically 
routes phone calls between the cellular, microcellular and cordless 
systems. The ACRE 117 also authorizes the cordless base station 115 to 
utilize channels. The ACRE 117 can be part of the TELCO 111 or can be a 
stand alone device. As previously noted, the cordless base station 115 and 
the PCC 101 together provide the limited range radio service 
conventionally known as cordless telephone service. Such service has 
become pervasive, conventionally using a few radio frequency channels in 
the VHF (very high frequency) or UHF (ultra high frequency) radio bands. 
The user of a radiotelephone should expect that radiotelephone service be 
available wherever he travels in the United States and that this service 
is provided at the lowest cost. It is also to be expected that 
radiotelephone service be provided in a portable unit that is as compact 
and inexpensive as possible. The PCC 101 is uniquely configured to meet 
this end. Furthermore, the cordless base station 115 is uniquely designed 
to provide telephone interconnect to the user's home telephone line when 
the user has the PCC 101 within the radio range of the cordless base 
station 115. 
A block diagram of the ACRE 117 is shown in FIG. 2. The ACRE 117 is 
connected to a TELCO 111 by an interface 202. The interface 202 controls 
and formats messages between the TELCO 111 and a processor 204. The 
processor 204 in combination with a control software memory 206 is the 
intelligence of the ACRE 117 and performs authorization, and 
authentication tasks and provides call routing information. A subscriber 
database 208 contains the data required by the processor 204 in order to 
perform the tasks discussed above. The ACRE 117 can be separate from the 
TELCO 111 as shown in FIG. 2 or can be part of the TELCO 111, usually part 
of the switching equipment. When the ACRE 117 is part of the TELCO 111 the 
ACRE 117 may not need the interface 202. Additionally, the functions of 
the ACRE may be performed by existing equipment at the TELCO. 
FIG. 3 shows a typical arrangement of coverage areas for the cordless, 
microcellular and cellular systems. The cordless system coverage area is 
the smallest and resides within the microcellular system. The 
microcellular system has intermediate coverage and resides within the 
cellular system. The coverage area of each system may depend upon but is 
not limited to the number of base stations in each system, antenna height 
of each base station and the power level used by each system. The user of 
the portable radiotelephone may relocate between the various coverage 
areas. The portable radiotelephone may change between systems based on but 
not limited to portable radiotelephone location, system availability, and 
user preference. 
The coverage areas of the systems are not limited to the particular 
arrangement as shown in FIG. 3. A coverage area may be independent of 
another coverage area or may partially overlap one or more other coverage 
areas. 
The cordless base station 115, conceptually, is a subminiature cellular 
system providing a single signaling channel which transmits outbound data 
messages in a fashion analogous to a conventional cellular outbound 
signaling channel, and receives service requests from a remote unit, such 
as a PCC 101. Proper service requests are granted with an assignment of a 
voice channel (made via the control channel) on the same or a second radio 
frequency to which the PCC 101 is instructed to tune for its telephone 
call. 
The basic implementation of a cordless base station is shown in FIG. 4. A 
conventional transmitter 301 and a conventional receiver 303 suitable for 
use in the 869 to 894 MHz and 824 to 849 MHz band of frequencies, 
respectively, being used for conventional cellular services, are coupled 
to a common antenna 305 via a duplexer 307. The power output of the 
transmitter 301 is limited to approximately 6 milliwatts so that 
interference to other services and other cordless telephone stations is 
minimized. The channel frequency selection is implemented by a frequency 
synthesizer 309 controlled by a logic unit 311. Within the logic unit 311 
is a microprocessor 313, such as a 68HC11 available from Motorola, Inc., 
or similar microprocessor, which is coupled to conventional memory devices 
315 which store the microprocessor operating program, base identification 
(BID) and customizing personality, and other features. Received and 
transmitted data is encoded/decoded and coupled between the receiver 303, 
the transmitter 301, and the microprocessor 313 by signaling interface 
hardware 317. The microprocessor instructions are conveyed and implemented 
by control hardware 319. Interface with the user's home landline telephone 
line is conventionally accomplished via a TELCO interface 321. Power is 
supplied from the conventional AC mains and backed-up with a battery 
reserve (all depicted as power 323). 
The PCC 101 is a portable radiotelephone transceiver which is shown in 
block diagram form in FIG. 5. A portable radio receiver 401, capable of 
receiving the band of frequencies between 869 and 894 MHz, and a portable 
transmitter 403, capable of transmitting with low power (approximately 6 
milliwatts in the preferred embodiment) on frequencies between 824 and 849 
MHz, are coupled to the antenna 405 of the PCC 101 by way of a duplexer 
407. The particular channel of radio frequency to be used by the 
transmitter 403 and the receiver 401 is determined by the microprocessor 
409 and conveyed to the frequency synthesizer 411 via the interface 
circuit 413. Data signals received by the receiver 401 are decoded and 
coupled to the microprocessor 409 by the interface circuit 413 and data 
signals to be transmitted by the transmitter 403 are generated by the 
microprocessor 409 and formatted by the interface 413 before being 
transmitted by the transmitter 403. Operational status of the transmitter 
403 and the receiver 401 is enabled or disabled by the interface 413. The 
interface also controls light emitting diodes, 415 and 417, which are used 
to indicate to the user which system the PCC 101 is currently receiving. 
Control of user audio, the microphone output and the speaker input, is 
controlled by audio processing circuitry 419. 
In the preferred embodiment, the microprocessor 409 is a 68HC11 
microprocessor, available from Motorola, Inc., and performs the necessary 
processing functions under control of programs stored in conventional ROM 
421. Characterizing features of the PCC 101 are stored in EEPROM 423 
(which may also be stored in the microprocessor, on-board EEPROM) and 
include the number assignment (NAM) required for operation in a 
conventional cellular system and the base identification (BID) required 
for operation with the user's own cordless base. 
The transmitter 403 of the PCC 101 has the capability of transmitting with 
the full range of output power which is required for operation in a 
conventional cellular system. This range of output power consists of six 
sets of output power magnitude ranging from a high output power level of 
approximately 600 milliwatts to a low output power level of 6 milliwatts. 
This six set range of output power is enabled when the PCC 101 is in the 
cellular system mode. 
According to the preferred embodiment of the present invention, the same 
PCC 101 is compatible with both the cordless and cellular telephone system 
103. This is accomplished by enabling the PCC 101 to operate in both a 
cordless and cellular telephone system 103 using only cellular telephone 
frequencies. 
The radiotelephone arrangement has desirable advantages for the user. The 
PCC 101, in combination with the cordless base station 115, can 
automatically route, via the ACRE 117, an incoming call to the telephone 
system in which the PCC 101 is located without inconveniencing the user. 
The TELCO 111, in combination with the ACRE 117, can automatically route 
an incoming call to the PCC 101 without inconvenience to the user. 
The priority established for the PCC 101 is that the cordless base station 
115 is the first desired path for a user's telephone call and the 
conventional cellular (or the microcell system) is the second choice, the 
process of implementing that priority is shown in FIG. 6. The depiction in 
FIG. 6 is of the PCC receiver's 401 reception of the outbound signaling 
channel or set of signaling channels transmitted from the cellular system, 
the cordless base, and the microcellular system relative to time. This 
diagram aids in the understanding of the unique scanning priority feature 
of the present invention. 
The PCC receiver 401 can be monitoring 431 the outbound message stream 
being transmitted from the cellular system signaling channel (which was 
selected from among the plurality of cellular signaling channels in 
conventional fashion). At the appropriate time, the PCC receiver 401 is 
instructed by its microprocessor 409 to tune to the frequency or one of 
the frequencies being used by the cordless base station 115 as a signaling 
channel. The PCC receiver 401 scans 433 the cordless base outbound 
signaling channel or channels for a period of time t.sub.2. If the 
signaling data stream is not received with sufficient quality, the PCC 
receiver 401 is returned to the previously selected signaling channel of 
the cellular system 103. It remains tuned to this signaling channel 435 
for a period of time, t.sub.1, before attempting another scan of a 
signaling channel of one of the alternative systems. The relationship of 
t.sub.1 and t.sub.2 is such that a cellular page message (that is, a 
radiotelephone call or other transmitted requirement) which is repeated, 
conventionally, after a 5 second pause will not be missed because the PCC 
receiver 401 was scanning an alternative system during both cellular page 
message transmission times. The time t.sub.1 must be greater than the sum 
of the pause between the two pages and the typical time to transmit two 
pages. The time t.sub.2 must be less than the time between the two pages. 
If the pause time is 5 seconds and the typical time to transmit a page is 
185.2 milliseconds, t.sub.1 must be greater than the 5.3704 seconds and 
t.sub.2 must be less than 5 seconds. After monitoring the cellular system 
signaling channel for a time t.sub.1, the PCC receiver 401 may be 
instructed to tune to the signaling channel or to the signaling channels, 
sequentially, of the microcell system, as shown at 437. If an adequate 
microcell signaling channel is not found during the scan of predetermined 
signaling channel frequencies, the PCC receiver 401 retunes to the 
cellular system signaling channel, as shown at 439. 
A scan to the signaling channels, 441, of the cordless base station 115 
which discovers a signaling data stream meeting appropriate quality 
requirements results in the PCC receiver 401 continuing to monitor the 
cordless signaling channel. The PCC receiver 401 remains on the cordless 
signaling channel without rescanning to another system until the PCC 101 
cannot receive the cordless basels transmitted signal for a continuous 5 
second period of time. 
The effect of this priority process is to give priority to the cordless 
base station 115 at the PCC 101. Once the signaling channel of the 
cordless base station 115 is discovered, the PCC 101 remains tuned to this 
channel. Thus, when the PCC 101 is initially tuned to the cellular system 
it will automatically switch to the cordless base station when it is 
possible to access the cordless base station. Once the PCC receiver 401 
has found the cordless base signaling channel, it remains tuned to that 
channel. When the FCC transceiver is first turned on, its first scan of 
signaling channels is the reestablished signaling channel or channels of 
the cordless base station 115. Of course, the user may override the 
automatic priority scanning hierarchy by entering an override code into 
the PCC 101. In this manner, the user may force the scanning of the 
cellular system signaling channels only, the cordless base signaling 
channels only, the microcellular system signaling channels only, or 
combinations of the systems. The user may also perform a call origination 
with a one time override to the system of his choice. 
Once the signaling channel of a system is being monitored, a visual 
indication is given to the PCC transceiver user. In the preferred 
embodiment, this indicator is a set of light emitting diodes (LEDs) 415, 
417, one of which uniquely illuminates to indicate to which system the PCC 
transceiver is tuned. Other indicators may alternately be used to convey 
the same information. For example, a system identifier may appear in the 
number display of the PCC 101, or a flashing symbol (having different 
rates of flashing) may be used. Nevertheless, this indication enables the 
user to determine which system he is in and decide whether he wishes to 
complete a radiotelephone call in the indicated system. 
In order for the PCC 101 to communicate with the cordless base station 115 
it must be authorized to use a particular channel. Authorization is 
required since the licensee of the cellular spectrum is required by the 
FCC to maintain control of its transmitters. The cordless base station 115 
is programmed to update its authorization periodically. To do this the 
personal base station 115 initiates a phone call to the ACRE 117. The ACRE 
117 responds with a connect message 502 (see FIG. 7) which contains a 
first random number that will be used in the authentication process. The 
cordless base station 115 responds with an authentication message 504. The 
authentication message 504 contains a cordless base station ID, a first 
authentication result calculated using the first random number, and a 
second random number. The ACRE 117 responds with an authorization and 
authentication message 506, which contains a second authentication result 
calculated using the second random number, and information describing 
which channels the cordless base station 115 can communicate over with the 
PCC 101. The cordless base station 115 responds with a registration 
message 507 which contains the PCC's 101 mobile identification number. The 
registration message 507 is only sent when a PCC 101 is in range of the 
cordless base station 115. The registration message 507 informs the ACRE 
117 to route the calls to the PCC 101 to the cordless base station 115. 
The ACRE 117 responds by sending a registration acknowledge message 508 to 
the cordless base station 115, which informs the cordless base station 115 
that the registration message 507 was received. The cordless base station 
115 then responds with a release message 509, which indicates if the 
authorization message sequence was successful. 
An important feature of a dual use radiotelephone system is to route calls 
through the "best" system, i.e. cordless, microcellular or cellular. Best 
can mean least expensive or clearest transmission or can be determined by 
some other variable. Which system is "best" can change during a phone call 
or as the PCC 101 moves in and out of the range of various systems. To 
accomplish this it is necessary for the ACRE 117 to be able to route calls 
to the cordless base station 115. To do this the ACRE 117 must know the 
telephone number of the cordless base station 115. One method for 
accomplishing this is to use caller identification provided by the TELCO 
111. Caller identification is designed to provide a telephone number 
and/or a subscriber name. 
The cordless base station 115 initiates a call to the ACRE 117 as part of 
the authorization and authentication process as shown in FIG. 8, at block 
510. The ACRE 117 receives the telephone number of the cordless base 
station 115 using caller identification (CLI). The ACRE 117 stores this 
information in block 512. The cordless base station 115 then sends its 
base identification number (BID) at block 514. The ACRE 117 uses BID to 
find the base station's 115 previous phone number, at block 516. At block 
518, the ACRE 117 determines if the phone number has changed. If the phone 
number has changed the ACRE 117 updates the telephone number for the 
cordless base station 115, at block 520. By this process the ACRE 117 has 
obtained or updated the cordless base station's 115 phone number which it 
can use to route subsequent calls. 
The updated phone number can also be used by the ACRE 117 to determine if 
the cordless base station 115 is located in an area where the cellular 
system provider is licensed to provide service by the FCC. For instance, a 
cellular system provider may only be licensed to provide service in the 
Chicago area. If a cordless base station 115 were moved by its owner 
outside the licensed area, the ACRE 117 would receive the base station's 
115 new phone number and deny service to the base station 115. This would 
prevent the base station 115 from transmitting over frequencies in an 
unlicensed area. Equally important, the cordless base station would still 
be calling the ACRE 117 in Chicago which would now be an expensive long 
distance telephone call. By denying service the owner is alerted to this 
potentially expensive situation. 
This process is shown in FIG. 9. The ACRE 117 after receiving the phone 
number in FIG. 8 determines if the phone number is an acceptable range, at 
block 522. If the phone number is not in an acceptable range the ACRE 117 
denies service, at block 524. If the phone number is in an acceptable 
range the phone call proceeds, at block 526. Since caller identification 
can provide either a telephone number and/or subscriber name, the process 
of FIG. 9 could use the subscriber name instead of the telephone number. 
If caller identification has not been implemented in the TELCO 111 system 
then the authorization and authentication message sequence must be altered 
to request cordless base station's 115 phone number periodically. Since, 
the cordless base station 115 is likely to stay at one phone number for 
extended periods of time the ACRE 117 would not require the cordless base 
station 115 to send its phone number every time it called the ACRE 117. 
However, upon initial installation of the cordless base station 115 the 
ACRE 117 would need the base station phone number. Also, when the base 
station moved to a new phone number and the user remembered to update the 
base station phone number the base station 115 must be able to report its 
new phone number if the ACRE 117 does not request the base station phone 
number. 
This process is described in FIG. 10, and begins with the cordless base 
station 115 initiating a call to the ACRE 117, at block 530. The ACRE 117 
responds with the connect message, at block 532. The cordless base station 
115 then determines if the connect message requested the base station 
phone number be sent, at block 534. If yes, then the processing continues 
at block 538; if no, the base station determines if its phone number has 
changed, at block 536. If the phone number has not changed, the processes 
is exited, at block 542. If the phone number did change in block 536, then 
the cordless base station 115 sends its phone number, at block 538. The 
ACRE 117 stores the phone number for subsequent call routing, at block 
540. 
A further embodiment of the invention provides the cordless base station 
115 with the capability to receive caller identification information via 
the TELCO interface 321. The cordless base station 115 can then store a 
plurality of caller identification messages in its memory 315. The caller 
identification messages contain a telephone number of the person trying to 
place a call to the cordless base station 115, and may include the name of 
the person or phone which originated the telephone call and a time and 
date stamp. 
The PCC 101 can be equipped to receive caller identification messages 
transmitted from the cordless base station 115 through its transmitter 301 
to the PCC's receiver 401. Since, the PCC 101 will not always be in range 
of the cordless base station, 115 it should only transmit the caller 
identification information when requested to do so by a request signal. 
The request signal can be initiated by a number of events. For instance, 
the user could initiate a request signal by a keypad sequence or voice 
command to the PCC 101 which would then send a caller identification 
recall message 550 to the cordless base station 115, as shown in FIG. 11. 
The cordless base station 115 would respond with a caller identification 
message 552 containing the caller identification messages stored in the 
cordless base station 115. Alternatively, the request signal could be 
initiated whenever the PCC 101 first comes within range of the cordless 
base station 115. Once the PCC 101 recognizes it is within range of the 
cordless base station 115, the PCC 101 could initiate a request signal and 
send a caller identification recall message 550 to the cordless base 
station 115. Finally, whenever the PCC 101 is in range of the cordless 
base station 115 and a telephone call is placed to the PCC 101 the ring 
signal should initiate the request signal. 
Turning now to FIG. 12, the preferred format for transmitting information 
between the cordless base station and the PCC, as well as specific 
messages are shown. In particular, FIG. 12-1 shows the reverse message 
format (i.e. from the PCC to the cordless base station) having a sync 
field 554 and a word field 556. Generally, the sync and word fields are 
alternately sent as shown in FIG. 12-1. FIG. 12-2 shows the word format 
for caller identification recall message 550 of FIG. 11. In particular, 
caller identification recall message 550 includes a scramble count field 
558 which is incremented for each word that is transmitted to insure that 
if the wrong cordless base station decodes a word, the next word will not 
be decoded. The caller identification recall message also includes a 
reverse cordless message 560 and a location number 562 indicating the 
location of the number being recalled. The caller identification recall 
message also includes a caller identification recall type field 564 which 
allows recalling by location number, recalling the most recent location, 
recalling the oldest location, recalling the next location and recalling 
the previous location. A reserve field 566 is also included. Finally, the 
caller identification recall message includes a message qualifier field 
568 and a parity field which is encoding the Bose-Chaudhurai-Hocquenghem 
(BCH) method. 
Turning now to FIG. 12-3, the general forward channel format is shown. In 
particular, the forward channel format includes a sync qualifier field 
572, a sync field 574, and a word field 576 which is periodically 
repeated. FIG. 12-4 shows the generic caller identification word format. 
In particular, the generic caller identification word format includes a 
scramble count field 578, a forward cordless message type field 580, and a 
word number.sub.3 field 582. The message also includes a FLIP field 584 
for indicating the FLIP state of the words which are being acknowledged. 
The message also includes a field 586 indicating that additional words are 
coming, followed by caller identification information field 588. A word 
number.sub.2-0 field 590 is then sent in the message. The word 
number.sub.3 and word number.sub.2-0 are used collectively to indicate 
which word of the caller identification message is being transmitted. A 
mobile station ID number field 592 indicates which mobile station (PCC) is 
allowed to communicate on the reverse cordless channel. Finally, a parity 
field 594 is sent. 
The caller identification information 588 of the generic caller 
identification word format may contain various types of data. Some 
specific examples of data are shown in FIGS. 12-5 through 12-9. The caller 
identification message is comprised of one or more words utilizing the 
generic caller identification word format and may contain the specific 
examples of data shown in FIGS. 12-5 through 12-9 for the caller 
identification information 588. 
In particular, the caller identification location number word shown in FIG. 
12-5 includes a location number field 566 followed by a reserve field 598 
and a recall field 600 for the caller identification information field 
588. The recall field is set to 1 to differentiate this word from the 
caller identification header word shown in FIG. 12-6. 
FIG. 12-6 shows the caller identification header word. The caller 
identification information field 588 for this word contains a month field 
602, a day field 604, hour field 606, minute field 608, line number field 
610, name type field 612, number preferred field 614, and recall field 
616. Fields 602, 604, 606, and 608 provide a time stamp of when the caller 
identification message was received by the cordless base station. The line 
number field 610 indicates on which telephone line the caller 
identification message was received. Name type field 612 indicates whether 
the ASCII caller identification name format of FIG. 12-8 or the compressed 
ASCII character caller identification name format of FIG. 12-9 will be 
utilized. The number preferred field 614 indicates the order of the name 
and number caller identification words. For example, a value of zero 
indicates that name words are sent first and a value of one indicates that 
number words are sent first. 
FIG. 12-7 shows the caller identification number word. The caller 
identification information field 588 for this word includes multiple digit 
fields 620. A predefined value could be entered into one of the digit 
fields to indicate the last word of a number and the end of the number. 
FIG. 12-8 shows a first caller identification name word having an ASCII 
format which is preferrably 8 bits long. A predefined value could be 
entered into one of the character fields to indicate the last word of the 
name and the end of the name. 
FIG. 12-9 shows a second caller identification name word having a 
compressed ASCII format which is preferrably 6 bits long. This compression 
is done to minimize transmission time. The compression only allows a 
limited number of characters to be utilized. A predefined value could be 
entered into one of the character fields to indicate the last word of the 
name and the end of the name. 
A radiotelephone and system for allowing the radiotelephone to operate in 
the cellular, microcellular or cordless communication systems has been 
described. In order to route calls to a cordless base station 115, it is 
necessary for the ACRE 117 to know the base station's 115 telephone 
number. One method for obtaining the cordless base station's 115 telephone 
number is to use caller identification provided by the TELCO 111 when the 
base station 115 calls in for authorization to the ACRE 117. Another 
method requires the ACRE 117 periodically request the base station's 115 
telephone number. This method also allows the base station 115 to send its 
telephone number when ever the base station's 115 telephone number has 
changed. Both methods insure the ACRE 117 has the telephone number of the 
base station 115 for proper call routing. Additionally, the cordless base 
station 115 can be provided with caller identification recognition 
capabilities. This allows the cordless base station 115 to store caller 
identification messages and transmit them to the PCC 101. 
To those skilled in the art it is obvious that many modifications can be 
made to the invention without departing from the spirit of the invention. 
For instance, the ACRE 117 can be performed by several pieces of 
equipment, which could be located separately from each other. Or the 
authorization function and equipment could be separate from the call 
routing equipment and function. Also it would be obvious to those skilled 
in the art to substitute any number of devices for the PCC 101 in 
receiving the caller identification information from the cordless base 
station. Such devices would include electronic appointment and address 
books or a modem in a portable computer. Any such modification is 
considered to be part of the inventor's exclusive rights is this 
invention. For a full understanding of the scope of the invention 
reference should be made to the appended claims.