Adjunct interface apparatus for a telephone set

A telephone set is disclosed which includes an adjunct interface module within the telephone set stand of the telephone set. This adjunct interface module converts the telephone set interface, which connects the telephone set to a premise switching system, to a different interface that is used by adjunct telephone equipment associated with the telephone set. Typically, the telephone set interface is a non-standard, or proprietary, interface, while the adjunct interface is the more common tip-ring interface.

BACKGROUND OF THE INVENTION 
The present invention relates to an adjunct interface module which is 
typically used to connect adjunct telephone equipment to a telephone 
switching system. 
An on-premise switching system, such as a private branch exchange (PBX) or 
a key/hybrid telephone system, typically provides an on-premise user with 
access to a set of telecommunication features through a nonstandard 
telephone set. The telephone set is nonstandard in that it is designed to 
connect to the telephone set interface provided by the on-premise 
switching system. The telephone set interface provided by the on-premise 
switching system can either have more conductors, different line voltages, 
and/or different signaling rates than a common telephone loop, or 
"tip-ring", interface provided by a central office. As a result of this 
different telephone set interface, the switching system is able to offer a 
set of features to the user at a better price/performance ratio than might 
be available with conventional, tip-ring telephone equipment. 
However, a user may have an investment in adjunct telephone set equipment 
that is built with the tip-ring telephone interface, e.g., a telephone 
answering machine, or built with yet another interface, such as an 
external alert interface. This adjunct equipment may offer the user 
services that may not yet be available, or affordable, in the user's 
premise switching system. As a consequence, for the user who would still 
like to use adjunct telephone equipment, on-premise switching vendors 
typically provide a physically separate adjunct interface module to the 
user to convert the adjunct telephone equipment interface to the telephone 
set interface of the premise switching system. 
SUMMARY OF THE INVENTION 
We have come to realize that the prior arrangements are disadvantageous 
from a number of standpoints. For example, since an adjunct interface 
module is a separate piece of equipment, it typically has costs that are 
associated with the separate packaging, provides the user with yet another 
box for which to allocate desk or storage space, and may require the user 
to configure the adjunct interface module for a particular adjunct. For 
instance, a user who would like his or her tip-ring answering machine to 
be used in conjunction with a nonstandard telephone set will have to 
allocate space for three pieces of equipment: the answering set, the 
adjunct interface module, and the telephone set. As a result, a certain 
amount of "box proliferation" results, i.e., the user who wants to access 
adjunct services must deal with yet another separate piece of equipment. 
A further problem exists when the adjunct interface module can provide a 
number of different adjunct interfaces over a particular cable. This 
requires the user to configure the adjunct interface module so that the 
appropriate adjunct interface is provided, via the cable, to a particular 
piece of adjunct equipment. For instance, an adjunct interface module may 
support either a tip-ring interface or an external alert interface (the 
former interface allows equipment such as an answering machine to be used 
while the later interface allows equipment to ring an alert, e.g., a 
bell). As a result, the user typically has to physically access the 
adjunct interface module in order to configure the appropriate adjunct 
interface, e.g., by choosing a particular switch setting on the internal 
circuitry of the adjunct interface module so that the tip-ring interface 
is provided for the answering machine. 
Therefore, in accordance with the invention, we have realized an apparatus 
for a telephone set which includes an adjunct interface module. In a 
preferred embodiment, the adjunct interface module is included within a 
set stand of the telephone set. Thus, the adjunct interface module is 
packaged in the telephone set stand and the additional space required by a 
physically separate adjunct interface module is eliminated. As a result, a 
user does not have to contend with box proliferation. 
In accordance with a feature of the invention, the adjunct interface module 
can be installed in the field to allow a user to easily re-configure a 
telephone set to the type of adjunct interface needed. 
In accordance with another feature of the invention, the user can 
reconfigure the adjunct interface module from the telephone set to provide 
the type of adjunct interface needed.

DETAILED DESCRIPTION 
FIG. 1 illustrates a single user telephone set configuration as known in 
the prior art. A user can receive or originate telephone calls by lifting 
handset 12 which is connected by electrical cord 13 to telephone housing 
21 of telephone set 11. Telephone set 11 is electrically connected via 
cable 14 to customer premise switching system 18 (typically a PBX or 
key/hybrid system). Switching system 18 is connected to a telephone 
central office by cable 19. The term "cable" is used herein to refer to a 
plurality of wires, or conductors, for interconnecting, both physically 
and electrically, two pieces of equipment. The term "interface" is used 
herein to refer to a specification of the interconnection between two 
pieces of equipment, the specification including the type, quantity, and 
function of the interconnecting wires and the type and form of signals 
present on the wires (e.g., see IEEE Standard Dictionary of Electrical and 
Electronics Terms, ANSI/IEEE Std. 100-1984, Third Edition). Thus two 
pieces of equipment with the same interface can be interconnected together 
by using a cable which supports that interface, i.e., a cable which falls 
within the interface specification. Although a particular cable can 
potentially support a number of different interfaces it is assumed herein, 
for simplicity, that a cable is uniquely identified by the interface 
associated with the cable in a particular example. 
Cable 19 supports a common telephone interface and for illustrative 
purposes represents one of a plurality of "tip-ring" connections to the 
central office. However, the interface supported by cable 14 is typically 
specific to switching system 18 and will have different signaling rates, 
line voltages, and/or a different number of actual wires within cable 14 
than cable 19, i.e., cable 14 supports a different interface from cable 
19. As a result, as taught in the prior art, a piece of adjunct equipment 
with a tip-ring interface, such as an answering machine, cannot be 
directly connected to cable 14 to be used in conjunction with telephone 
set 11 (e.g., to provide an answering machine service), without first 
providing a physically separate adjunct interface module to convert the 
tip-ring interface of the answering machine to the interface of switching 
system 18. This is shown in FIG. 1, where the interface of switching 
system 18 is extended, via cable 141, to adjunct interface module 100 
which converts the switching system interface supported by cable 141 to 
the tip-ring interface of adjunct 16 supported by cable 15. Unfortunately, 
since an adjunct interface module is a separate piece of equipment, it 
typically has costs that are associated with the separate packaging and 
provides the user with yet another box to be concerned about, i.e., "box 
proliferation" (e.g., allocation of space, power connections, 
configuration, etc.). 
However, in accordance with the invention, we have realized an apparatus 
for a telephone set which includes an adjunct interface module. Thus, the 
adjunct interface module is integrated, or packaged, into the telephone 
set and the additional space required by a physically separate adjunct 
interface module is eliminated. As a result, a user does not have to be 
concerned about box proliferation. In addition, by integrating the adjunct 
interface module into the telephone set, in accordance with the invention, 
the user can be provided with the capability of configuring the adjunct 
interface module from the telephone set. As shown in FIG. 2, 
representative answering machine adjunct 16 is directly connected to 
telephone set stand 17, with the conversion between the interface of 
adjunct 16 and the interface of switching system 18 being accomplished by 
the adjunct interface module within the telephone set stand. Thus, 
separate adjunct interface module 100 and cable 141 are eliminated and the 
user may be also provided with the capability to configure the adjunct 
interface module from the telephone set. 
Before describing the mechanical aspects of the inventive concept, 
reference is made to FIG. 3 which depicts an illustrative electrical block 
diagram of telephone set 11, embodying the principles of the invention. It 
should be noted that the term "connector" as used herein is representative 
of any of the well-known methods and techniques for interconnecting two 
wires together. Illustratively, a connector is assumed to comprise a 
"jack" and a "plug". Telephone set 11 is comprised of telephone housing 21 
and telephone set stand 17. As is taught in the prior art, telephone 
electronics 22 is enclosed within telephone housing 21. (Telephone 
electronics 22 comprises the circuitry which allows a user to place a 
telephone call to, or receive a telephone call from, switching system 18, 
and includes input/output 24 (e.g., dial-pad, switchhook, etc.), telephone 
processor 26, and line interface 28.) Telephone electronics 22 is 
connected to cable 14 by lead 23 via jack 410 and plug 411. Telephone 
housing 21 utilizes telephone set stand 17 to provide better access and 
viewing angle for the user. Within telephone set stand 17 is module 
housing 31. Module housing 31 contains adjunct interface electronics 32 
which converts the interface of adjunct 16 to the interface of switching 
system 18. Adjunct interface electronics 32 is connected to cable 15 by 
lead 34 via jack 430 and plug 431, and to cable 14 by lead 33 via jack 420 
and plug 421, and lead 23. 
FIG. 4 illustrates a cross section of telephone set 11. The implementations 
of the physical arrangement itself, such as mounting connectors, printed 
circuit boards, etc., use techniques taught in the prior art. Within 
telephone housing 21 is circuit board 220 which may be of any desired type 
of circuit board (e.g., a rigid double-sided printed wiring board) for 
carrying telephone electronics 22, jacks 410 and 420, and lead 23 of FIG. 
3. It should be noted that housing 21 is so configured as to allow access 
to jacks 420 and 410, which are the receptacles for plug 421 on circuit 
board 320, and plug 411 on cable 14, respectively. Within telephone set 
stand 17 is module housing 31. Module housing 31 contains circuit board 
320 (e.g., a rigid double-sided printed wiring board) which carries 
adjunct interface electronics 32, plug 421, jack 430, and leads 33 and 34 
of FIG. 3. Plug 421 when inserted into jack 420 provides the electrical 
connectivity to cable 14 and the physical connection to mount circuit 
board 320 to the bottom of telephone housing 21. However, to provide 
additional support to circuit board 320, an additional restraint can also 
be provided as illustrated by tab 450 which represents one of any number 
of tabs that may be mounted to telephone housing 21 to hold circuit board 
320 in place. 
Over circuit board 320 is placed module hosing 31, which can be connected, 
in any number of well-known ways, to telephone housing 21. (It is 
preferable that module housing 31 be removable from set housing 11 to 
facilitate later installation or replacement of circuit board 320.) It 
should be noted that module housing 31, as shown in FIG. 4, is so 
configured as to allow access to jack 430. Module housing 31, though not 
specifically required by the inventive concept, does provide additional 
protection to circuit board 320 and the user, if the telephone set stand 
is removed. Additionally module housing 31 can be constructed, in any 
number of well-known ways, to also function as a wall mount for telephone 
set 21 when set telephone set stand 17 is removed, which would then 
require that module housing 31 be present to protect circuit board 320. 
Finally, telephone set stand 17 fits over module housing 31 and is 
connected to telephone set housing 21 in any number of well-known ways. As 
illustratively shown herein, telephone set stand 17 is so configured as to 
allow cables 14 and 15 to pass through the telephone set stand. 
The arrangement as described herein also allows circuit board 320 to be 
field-installable. Specifically, since circuit board 320 is mounted to 
telephone housing 21 by plug 421 and tab 450, a user is able to change 
circuit board 320 to a different board (for either a different function or 
for maintenance) without exposing circuit board 220 to user contact. As a 
result, the telephone service provided by telephone set 11 is not 
interrupted and telephone set 11 is additionally protected from damage by 
the user. 
In addition, adjunct interface electronics 32 may support a number of 
different adjunct interfaces, e.g., a tip-ring interface or an external 
alert interface. As a result, this requires the user to configure the 
appropriate adjunct interface before connecting a particular piece of 
adjunct equipment. For instance, in order to connect a tip-ring answering 
machine, to adjunct interface electronics 32, the user must first 
configure adjunct interface electronics 32 to support a tip-ring 
interface. Typically, this would be done by the user, in the prior art, by 
physically accessing adjunct interface electronics 32 in order to choose a 
particular switch setting associated with the tip-ring interface. However, 
an advantage of integrating the adjunct interface module into the 
telephone set is that the user can be provided with the capability of 
configuring adjunct interface electronics 32 from telephone set 11. To 
this end, as illustrated in FIG. 5, register 35 and jack 520 are added to 
telephone electronics 22. Register 35 is connected to telephone processor 
26 by lead 29 and to jack 520 by lead 36. The output of register 35 is 
typically a data value herein associated with a particular one of the 
adjunct interfaces supported by adjunct interface electronics 32. The user 
can alter the output of register 35 via input/output 24 in any number of 
well-known ways. For example, a predefined touch-tone sequence can be 
input by the user through the dial-pad of telephone set 11, i.e., 
input/output 24, and provided to telephone processor 26 which then can 
alter the output of register 35 to a data value associated with the 
touch-tone sequence. The output of register 35 is then provided to adjunct 
interface electronics 32 via plug 521 and lead 63. Adjunct interface 
electronics 32 receives the data value from lead 63 and provides the 
particular adjunct interface, associated with the received data value, on 
cable 15. As a result, the user, via input/output 24, can alter the 
characteristics of adjunct interface electronics 32, e.g., the user can 
change the interface from a tip-ring interface to an external alert 
interface without having to physically access adjunct interface 
electronics 32. 
The present invention has been described in terms of an illustrative 
embodiment. However, it should be realized that the invention is not 
limited to this particular embodiment and that additional embodiments, 
modifications and applications which will become obvious to those skilled 
in the art are within the spirit and scope of the invention.