Method for automatically discriminating low-speed interface units installed in an optical data transmission apparatus together with automatically confirming the installation

Code data of input type and output type low-speed interface units installed in one and other optical data transmission apparatus, placed opposite to and operatively connected to each other, are compared automatically in the one and the other optical data transmission apparatus respectively with code data of input type and output interface units in the other optical data transmission apparatus, sent from the other to the one optical data transmission apparatus and with code data of input type and output interface units in the one optical data transmission apparatus, sent from the one to the other optical data transmission apparatus.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to optical data transmission apparatus 
including low-speed interface units, and in particular, to a method for 
automatically discriminating low-speed interface units installed in the 
optical data transmission apparatus together with automatically confirming 
the installation of the low-speed interface units that are occasionally 
installed in the optical data transmission apparatus in compliance with 
data newly required to be transmitted through the optical data 
transmission apparatus. 
2. Description of the Related Art 
FIG. 1 shows a block diagram of typical optical data transmission apparatus 
of the related art, citing an instance of optical data transmission 
apparatuses 100 and 200 provided in stations A and B respectively. 
Stations A and B are placed opposite to each other at a distance as far as 
50 km, and data transmission is performed between the stations through the 
distance by using optical transmission means. 
The optical data transmission apparatus 100 in station A comprises a signal 
transmitter 101, a signal receiver 102 and a control unit 103. As in same 
as optical data transmission apparatus 100, optical data transmission 
apparatus 200 in station B comprises a signal transmitter 201, a signal 
receiver 202 and a control unit 203. The signal transmitter 101 includes 
input type low-speed interface units (IIU) 1, a multiplexing unit (MUX) 2 
and an optical signal sending unit (OS) 3, and same as signal transmitter 
101, signal transmitter 201 includes IIU 7, MUX 8 and OS 9. The signal 
receiver 102 in station A includes an optical signal receiving unit (OR) 
13, a demultiplexing unit (DMUX) 12 and output type low-speed interface 
units (OIU) 11, and same as signal receiver 102, signal receiver 202 
includes OR 4, DMUX 5 and OIU 6. In the above, IIUs 1 and 7, and OIUs 11 
and 6 comprise the same number of units respectively, and the units in IIU 
1 correspond to the units in OIU 6 and the units in IIU 7 correspond to 
the units in OIU 11 in regard to the sorts of the data to be transmitted, 
respectively. The stations A and B are transmissively connected so that an 
optical signal from OS 3 in signal transmitter 101 is sent to OR 4 in 
signal receiver 202 through an optical transmission line 301 and the 
optical signal from OS 9 in signal transmitter 201 is sent to OR 13 in 
signal receiver 102 through an optical transmission line 302. 
Generally, data sent between stations, like stations A and B, are divided 
into two categories. One is a data, which will be called a "payload data" 
hereinafter, required by a client to send between the stations; and the 
other is a liaison data, which will be called "control data" hereinafter, 
used for maintaining and/or controlling the optical data transmission 
apparatus in the stations. The payload data are transmitted on a plurality 
of ordinary channels and the control data is usually transmitted on an 
overhead bit (OHB) channel. 
In FIG. 1, payload data are transmitted between stations A and B as 
follows: payload data to be sent from station A to station B are sent to 
the units (UNIT-1 to UNIT-n) of IIU 1 in signal transmitter 101 in 
compliance with the sort of the payload data and interfaced respectively 
so as to be multiplexed by the following MUX 2; a multiplexed signal from 
MUX 2 is sent to OS 3 and converted to an optical signal; the optical 
signal from OS 3 is transmitted through the optical transmission line 301 
and received at OR 4 in signal receiver 202; the optical signal received 
at OR 4 is converted to an electric signal and sent to DMUX 5; the 
electric signal sent to DMUX 5 is demultiplexed; and a demultiplexed 
signal from the DMUX 5 is sent to the units (UNIT-1' to UNIT-n') of OIU 6 
so as to be interfaced to the payload data respectively. 
Concretely explaining the above by citing an instance of transmitting 
telephone signals, the telephone signals are transmitted from station A to 
B as follows: 45 megabit/sec (Mb/s) data produced by multiplexing 
telephone signals at telephone switchboards, not depicted in FIG. 1, are 
sent to the units (UNIT-1 to UNIT-n) of IIU 1 and interfaced, for 
instance, inverted from bipolar signals to unipolar signals; the 
interfaced (unipolar) signals from IIU 1 are sent to MUX 2 and multiplexed 
to 1.8 gigabit/sec (Gb/s) data thereby; the 1.8 Gb/s data (multiplexed 
signal) is sent to OS 3 and converted to an optical signal; the optical 
signal from OS 3 is transmitted to OR 4 in signal receiver 202 through the 
optical transmission line 301; the optical signal is converted to an 
electric signal at OR 4; the electric signal from OR 4 is demultiplexed by 
DMUX 5; and the demultiplexed signals from DMUX 5 are sent to the units 
(UNIT-1' to UNIT-n') of OIU 6 and interfaced to the 45 Mb/s data 
respectively. 
The transmission of payload data are performed from station B to A same as 
the above. That is: payload data sent to signal transmitter 201 are 
interfaced by IIU 7; interfaced signals from IIU 7 are multiplexed by MUX 
8; a multiplexed signal from MUX 8 is sent to OS 9 so as to be converted 
to an optical signal; the optical signal from OS 9 is transmitted to OR 13 
in signal receiver 102 through optical transmission line 302; the optical 
signal received at OR 13 is converted to an electric signal and 
demultiplexed by DMUX 12; and the demultiplexed signals from DMUX 12 are 
sent to OIU 11 and interfaced to the payload data. 
In the above transmission of the payload data between stations A and B, the 
numbers of units of IIU 1 and OIU 6 and of IIU 7 and OIU 11 are determined 
by sorts of payload data. Therefore, when other new sorts of payload data 
are required to be sent between stations A and B, units corresponding to 
the new sorts of payload data must be installed to IIUs 1 and 7 and OIUs 6 
and 11 respectively. 
In FIG. 1, it is looked as if the number of units in each IIU and OIU is 
"n". However, a unit depicted by a dotted box marked by subsidiary numbers 
"k" in IIUs 1 and 7 or "k'" in OIUs 6 and 11, for example UNIT-k in IIU 1 
or UNIT-k' in OIU 6, represents a unit to be newly installed in compliance 
with a required new sort of payload data, so that the number of units 
installed in each IIU and OIU is "n-1" before newly installing the unit 
marked by "k" or "k'" thereto. The unit marked by "k" or "k'" will be 
called the "UNIT-k" or "UNIT-k'" respectively hereinafter. In other words, 
FIG. 1 shows a case that each IIU and OIU has n positions of units to be 
installed and has n-1 positions of units having been installed. 
In FIG. 1, when a payload data corresponding to UNIT-k is required to be 
sent between stations A and B, UNIT-k must be installed in IIUs 1 and 7 
respectively and UNIT-k' must be installed in OIUs 6 and 11 respectively. 
The installation of the UNITs-k and UNITs-k' is performed by a field 
installer individually at stations A and B. In the related art, after the 
installation is over at stations A and B, confirmation whether the 
installation is performed correctly is performed by a professional 
operator of the control units 15 and 25. When the installation is 
confirmed so as to be done correctly, all the units installed in IIUs and 
OIUs in stations A and B are started by the operators at stations A and B. 
Such discrimination and confirmation of the units of IIUs and OIUs 
performed in stations A and B are the subject of the present invention. 
That is, in the related art, the confirmation of the installation has been 
performed by operators, manually treating control units 103 and 203 
individually in stations A and B. Different from the above related art, in 
the present invention, the discrimination and confirmation are performed 
automatically by a discriminating system including improved control units 
in stations A and B. The details of the related art will be explained, 
citing an instance of station B in reference to FIG. 2. 
In FIG. 2, the same reference numeral or symbol as in FIG. 1 designates the 
same apparatus or unit as in FIG. 1. Every unit of OIU 6 and that of IIU 7 
have code data corresponding to a sort of payload data. For instance, cord 
"09" is used for DS3 interface and cord "03" is used for DS1/DS2 convert 
module interface; wherein, DS3 and DS1/DS2 convert modules are well known 
as the typical interfaces, in American National Standard for 
Telecommunications. 
After UNIT-k and UNIT-k' are newly installed in IIU 1 and OIU 11 
respectively in optical data transmission apparatus 100 and in IIU7 OIU 6 
and IIU 7 respectively in optical data transmission apparatus 200 by the 
field installers in stations A and B respectively, the professional 
operators confirm whether the UNITs-k and UNITs-k' are installed in 
correct positions in stations A and B. In the related art, the 
discrimination and confirmation are performed in station B as follows: in 
FIG. 2, the control unit 203 includes a micro processing unit (MPU) 203-1; 
under operation, which is performed by the operator in station B, of 
terminal board 25 in station B, MPU 203-1 sends selecting signals (SEL-1' 
to SEL-n') to OIU 6 and selecting signals (SEL-1 to SEL-n) to IIU 7 
respectively in a polling cycle such as 0.5 sec, for polling the code data 
of units installed in OIU 6 and IIU 7. The polled code data from OIU 6 and 
IIU7 are sent back to MPU 203-1 through data buses DB-1 and DB-2 
respectively and displayed on a display unit, not depicted in FIG. 2, 
provided to terminal board 25; the operator in station B operates terminal 
board 25 for discriminating and confirming whether the install positions 
of UNIT-k' in OIU 6 and UNIT-k in IIU 7, observing the display unit; and 
if the positions are confirmed so as to be correct, the operator operates 
MPU 203-1 through terminal board 25 so that the units of OIU 6 and IIU 7 
start to operate by start signals START-1' to START-n' and START-1 to 
START-n sent from MPU 203-1 to OIU 6 and IIU 7 respectively. Same as the 
above, in station A, the discrimination and confirmation of the units 
installed in IIU 1 and OIU 11 and re-starting the units if the 
confirmation results are correctly performed by the operator in station A, 
observing the indicator unit and operating MPU in control unit 103 through 
terminal board 15. Thus, in the related art, the discrimination and 
confirmation of the units installed in IIU and OIU and re-starting the 
operation of the units must be performed by manually operating the MPU in 
the control unit through the terminal board at each station, which has 
been too much complicated to a field worker for installation, who will be 
called a "field installer" hereinafter. Accordingly, in the related art, 
the professional operator who can treat the MPU through the terminal board 
is required to be dispatched to each station. 
In addition to the problem mentioned above, there is another problem for 
the field installer. In case of FIGS. 1 and 2, UNITs-k and UNITs-k' are 
newly installed in IIUs and OIUs in stations A and B respectively in 
compliance with the transmission of a new sort of payload data. This means 
that there are some spare positions for installing the new units of IIU 
and OIU in FIGS. 1 and 2. However, it occurs that even though all 
positions for the units are occupied, still other units are required to be 
installed in IIUs and OIUs in compliance with other sorts of payload data. 
Usually, MUX and DMUX have sections corresponding to the sorts of the 
payload data. Therefore, when there is possibility of transmitting new 
sorts of payload data, sections corresponding to the new sorts of payload 
data are previously provided in MUX and DMUX and switching units for 
selecting the sections are provided in MUX and DMUX or in IIU and OIU. 
FIG. 5 shows a case of providing a switching unit 61 in OIU 6 and a 
switching unit 71 in IIU 7 in station B. In FIG. 5, the same reference 
numeral or symbol as in FIG. 2 designates the same unit or station as in 
FIG. 2. In the related art, switching unit 61 includes switching elements 
SW-1' to SW-n' and switching unit 71 includes switching elements SW-1 to 
SW-n, and switching units 61 and 71 communicate to each other. FIG. 5 
shows a case that three sections are provided in DMUX 5 and MUX 8 
respectively, corresponding to three sorts of payload data to be 
interfaced by each unit of OIU 6 and IIU 7. For example, when the 
switching element is switched to connect with an upper position as shown 
in SW-1' or SW-1 in FIG. 3, the payload data is a sort of data to be 
interfaced from DS 1 to VT 1.5. When the switching element is switched to 
connect with a middle position as shown in SW-2' or SW-2 in FIG. 3, the 
payload data is a sort of data to be interfaced from DS 1 to DS 2. When 
the switching element is switched to connect with a down position as shown 
in SW-k' or SW-k in FIG. 3, the payload data is a sort of data to be 
interfaced from a bipolar signal to a unipolar signal in DS 3. When 
signals mentioned above are output from DMUX 5 and input to MUX 8 
respectively, UNIT-1' to UNIT-n' in OIU 6 and UNIT-1 to UNIT-n in IIU 7 
are installed so that each of the units corresponds to respective sort of 
signal. Each unit of OIU 6 and IIU 7 has a data code corresponding to the 
sort of payload data. Therefore, in the related art, when the units of OIU 
6 and IIU 7 are installed to corresponding to the sorts of payload data, 
MPU 203-1 in control unit 203 gathers the data code from the units in OIU 
6 and IIU 7 to MPU 203-1 through data buffers DB-1 and DB-2 respectively 
and sends switching signals to SW-1' to SW-n' in SW 61 and to SW-1 to SW-n 
in SW 71 respectively so that the switch elements are connected to the 
sections of the DMUX 5 and MUX 8 so as to correspond to the units in OIU 6 
and IIU 7 respectively. Thus, in the related art, the switching is 
performed automatically by MPU 203-1. However, there has been a problem 
that if a wrong unit is installed in OIU 6 or IIU 7 because of a mistake 
due to the field installer, the switching is performed in accordance with 
the wrong code data from the wrong unit automatically by MPU 203-1, so 
that wrong connection is performed by a switching element, however nobody 
knows about the wrong connection. 
SUMMARY OF THE INVENTION 
Therefore, an object of the present invention is to improve a field work of 
discriminating and confirming the units installed in IIUs and OIUs in the 
optical data transmission apparatuses, placed opposite to each other, so 
that the field work can be performed only by a field installer, not 
requiring a professional operator. 
Another object of the present invention is to reduce field installation 
costs having been spent on the field worker. 
Still another object of the present invention is to increase reliability of 
the field work. 
The above objects are accomplished by permitting the MPUs of the control 
units in the apparatuses, e.g. the apparatuses at stations A and B, 
automatically transmit the code data of the units installed in IIU and OIU 
in each station from station A to station B and vice versa by using OHB 
channels running between stations A and B, and automatically compare code 
data of the units installed in IIU and OIU in station A with the code data 
of IIU and OIU in station B, when the code data is transmitted from 
station B to A and also to compare the code data of the IIU and OIU in 
station B with the code data of the IIU and OIU in station A, when the 
code data is transmitted from station A to B. 
Thus the units installed in IIU and OIU in each optical data transmission 
apparatus in stations A and B placed opposite to each other are 
discriminated and confirmed whether they are correctly installed 
automatically by MPU in each optical data transmission apparatus. The 
start of each MPU is performed by a field installer dispatched to stations 
A and B respectively, not requiring any help of a professional operator 
for operating MPU.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
For the sake of comparing a preferred embodiment of the present invention 
with the prior art, the embodiment will be explained with an optical data 
transmission apparatus in station B in reference to FIG. 3. In FIG. 3, the 
same reference numeral or symbol as in FIG. 2 designates the same unit or 
part as in FIG. 2. 
In FIG. 3, station B includes a control unit 204 which is functionally same 
as the control unit 203 in FIG. 2 but improved by having, a data bus (DATA 
BUS) DB-3 provided from DMUX 5 to control unit 204 and DATA BUS DB-5 
between MUX 8 and control unit 204. The control unit 204 includes MPU 
204-1 same as MPU 203-1 in FIG. 2, however having processing capacity 
larger than that of MPU 203-1 and memory units MEM-1 and MEM-2. 
There is no depiction about station A in FIG. 3, however, station A also 
has the same configuration as in station B shown in FIG. 3. 
After the units K and K' are installed in IIUs 1 and 7 and OIUs 11 and 6 in 
stations A and B by the field installers at stations A and B, the field 
installers at stations A and B contact to each other through the OHB 
channel so as to perform the discrimination and confirmation of the units 
installed in the IIUs and the OIUs in stations A and B by operating 
control units 15 and 25 through terminal boards 15 and 25 respectively. In 
station B shown in FIG. 3 for example, the discrimination and confirmation 
of the units installed in IIU 7 and OIU 6 are performed automatically by 
control unit 204, in particular, by MPU 204-1 in control unit 204 in 
accordance with the following steps: 
(1) (RECEIVE 1st AND 2nd CODE DATA FROM STN-A) 
code data, which will be called first code data hereinafter, of the units 
installed in IIU 1 and code data, and second code data, of the units 
installed in OIU 11 in station A (STN-A) (see FIG. 1) are sent 
respectively to station B (STN-B) through the OHB channel running along 
optical transmission line 301 so as to appear at an OHB channel section of 
DMUX 5, automatically by the MPU in the control unit in STN-A through 
terminal board 15 operated by a field installer at STN-A (see FIG. 1); 
(2) (TRANSFER 1st AND 2nd CODE DATA TO MEM-1) 
the first and the second code data at the OHB channel section of DMUX 5 are 
transferred respectively to MEM-1 through data bus DB-3 automatically by 
MPU 204-1; 
(3) (POLL 3rd AND 4th CODE DATA) 
code data, which will be called third code data hereinafter, of the units 
in IIU 7 and code data, which will be called fourth code data hereinafter, 
of the units in OIU 6 are polled respectively by selecting signals SEL-1 
to Sel-n and SEL-1' to Sel-n' provided from MPU 204-1, automatically by 
MPU 204-1; 
(4) (TRANSFER 3rd AND 4th CODE DATA TO MEM-2) 
the third and the fourth code data are transferred respectively to MEM-2 
through DB-1, DB-2 and DB-5 automatically by MPU 204-1; 
(5) (TRANSFER 3rd AND 4th CODE DATA TO MUX) 
the third and the fourth code data are also transferred respectively to an 
OHB channel section of MUX 8 through DB-2 and DB-5 automatically by MPU 
204-1; 
(6) (SEND 3rd AND 4th CODE DATA TO STN-A) 
the third and the fourth code data transferred to MUX 8 are transmitted to 
STN-A through the OHB channel running along optical transmission line 302 
(see FIG. 1) automatically by MPU 204-1, which is functionally same as the 
first and the second code data are sent from STN-A to STN-B, which has 
been described in step (1); 
(7) (COME 3rd, 4th CODE DATA WITH 2nd, 1st CODE DATA) 
the third and the fourth code data stored in MEM-2 are read into MPU 204-1 
through a data bus DB-6 and the first and the second code data stored in 
MEM-1 are read into MPU 204-1 through a data bus DB-4 so that the third 
code data are compared with the second code data and the fourth code data 
are compared with the first code data respectively in MPU 204-1 
automatically, wherein, these comparisons are performed so that the code 
data of IIU in one station and OIU in other station set opposite to each 
other in a train of data transmission flow are compared; 
(8) (START TO OPERATE IIU AND OIU IN STN-B) 
when the comparing results in step (7) are correct, in other words, when 
the third code data are same as the second code data and the fourth code 
data are same as the first code data, IIU 7 and OIU 6 begin operating by 
start signals START-1 to n and START-1' to n' respectively, automatically 
by MPU 204-1, which means that STN-B starts to operate normally; 
(9) (SEND WAIT SIGNAL TO STN-A) 
when there is at least one fault in the comparing results in step (7), a 
wait signal is sent to STN-A automatically by MPU 204-1; and 
(10) (RECHECK THE STATE OF INSTALLATION) 
when the wait signal is sent to STN-A, a wait signal sent from STN-A is 
received at STN-B as far as units related to data transmission in STNs-A 
and B operate normally and optical data transmission lines 301 and 302 are 
normal, then the field installer at STN-B rechecks the installed state of 
units in IIU 7 and OIU 6, until the wait signal sent from STN-A disappears 
and STN-B starts to operate normally in accordance with MPU 204-1. 
The above steps are shown by a flow chart in FIG. 4. The same numerals and 
captions as in the description of the above steps are used in FIG. 4. 
Incidently, in the prior art, the steps automatically performed by CPU 
204-1 in the flow chart of FIG. 4 had to be performed one by one by a 
professional operator, because the steps have been too hard to be 
performed by the field installer. 
Thus, in stations A and B, the discrimination and the confirmation of the 
units installed in IIU and OIU are automatically performed by the MPU in 
the control unit and the operation of the terminal board for controlling 
the MPU is much improved so as to be performed only by the field 
installer. 
When optical data transmission apparatuses 100 and 200 in stations A and B 
include the switching unit in OIU and IIU respectively as shown in FIG. 5, 
a problem occurred in the related art as stated before. However, the 
method embodying the present invention also solves this problem. That is, 
even though the apparatus includes the switching unit, the units in OIU 
and IIU can be discriminated and confirmed automatically by the MPU in 
each station. 
As described in the steps in reference to FIG. 4, the discrimination and 
confirmation of the units in OIU and IIU are performed at the one station 
(station B) by using the code data of units in IIU in other station 
(station A) as reference data and by using the OHB channel for 
transmitting the reference data between stations A and B. Accordingly, if 
a trouble such that the reference data are not sent to station B from 
station A occurs, the discrimination and confirmation could not be 
performed by the method. Such trouble will probably occur in case that the 
field installer at station A is absent or there is an accident on a 
transmitting route of the reference data between stations A and B. 
For avoiding such trouble from occurring, a method is required to be added 
to the steps described in reference to FIG. 4. The additional method will 
be described in reference to FIG. 6, citing an instance of station B same 
as in FIG. 3. In FIG. 6, the same reference numeral or symbol as in FIG. 3 
or 5 designates the same unit or apparatus as in FIG. 3 or 5. 
In FIG. 6, a memory MEM-3 and a data bus DB-9 connected between MEM-3 and 
MPU 204-1 are added in control unit 204. The field installer at station B 
operates terminal board 25 so that data code, which will be called fifth 
data code hereinafter, for new units intended to be installed or exchanged 
in IIU 7 and OIU 6 are stored in MEM-3. Then, the field installer installs 
the new units or exchanges to new units in OIU 6 and IIU 7 and starts to 
operate MPU 204-1 through terminal board 25. Then, same as performed in 
FIG. 4, the third and the fourth code data are transferred to MEM-2 and 
stored therein. And, the third and fourth code data are compared with the 
fifth code data stored in MEM-3, automatically by MPU 204-1. That is, the 
fifth code data stored in MEM-3 are used instead of the first and second 
code data stored in MEM-1. When the third and fourth code data are 
confirmed to be correct by the comparison, the switching elements (SW-1' 
to SW-n') in switching unit 61 and the switching elements (SW-1 to SW-n) 
in switching unit 71 are switched in accordance with the switching signals 
sent from MPU 204-1 through DB-7 and DB-8 respectively, automatically by 
MPU 204-1. Different from the steps described before in reference to FIGS. 
3 and 4, the above steps described in reference to FIG. 6 are performed 
individually in station B. The same steps as in FIG. 6 are performed also 
individually in station A. In the additional method performed in reference 
to FIG. 6, the field installer must store the fifth code data by operating 
terminal board 25. This operation is not complicated, and the other 
confirmation of the units installed in OIU 6 and IIU 7 and the switching 
of switching units 61 and 71 are performed automatically by MPU 204-1. 
Therefore, the additional method performed in reference to FIG. 6 is 
carried out only by the field installer, not requiring any help of a 
professional operator of MPU. 
In the above description of the steps described in reference to FIGS. 3 and 
6, the discrimination and confirmation of the units installed in IIU 7 and 
OIU 6 are performed in case of the optical data transmission apparatus 200 
provided in station B. However, such discrimination and confirmation are 
not only applied to the optical data transmission apparatus but also to a 
general data transmission apparatus such as a radio wave data transmission 
apparatus. In case of the general data transmission apparatus, a general 
data signal receiver and a general data signal transmitter are used for 
signal receiver 202 and signal transmitter 201 respectively and a data 
signal receiving unit and a data signal transmitting unit can be used 
instead of optical signal receiving unit OR 4 and optical signal sending 
unit OS 9 respectively (see FIG. 1), which is well realized by a person 
skilled in the art.