<s>
Automatic	B-Application
message	I-Application
accounting	I-Application
(	O
AMA	O
)	O
provides	O
detailed	O
accounting	O
for	O
telephone	O
calls	O
.	O
</s>
<s>
In	O
centralized	O
AMA	O
(	O
CAMA	O
)	O
,	O
the	O
originating	O
Class	B-Device
5	I-Device
telephone	I-Device
switches	I-Device
used	O
automatic	O
number	O
identification	O
(	O
ANI	O
)	O
and	O
multi-frequency	O
(	O
MF	O
)	O
signaling	O
to	O
send	O
the	O
originating	O
and	O
dialed	O
telephone	O
numbers	O
to	O
the	O
Class	B-Device
4	I-Device
toll	O
connecting	O
office	O
.	O
</s>
<s>
The	O
Class	B-Device
4	I-Device
office	O
recorded	O
this	O
information	O
with	O
punched	O
tape	O
machines	O
on	O
long	O
strips	O
of	O
paper	O
,	O
that	O
had	O
approximately	O
the	O
width	O
of	O
a	O
hand	O
.	O
</s>
<s>
In	O
Bell	O
System	O
telephone	O
exchanges	O
,	O
particularly	O
the	O
5XB	B-Device
switches	I-Device
,	O
information	O
from	O
the	O
marker	B-Device
told	O
the	O
sender	O
that	O
the	O
call	O
required	O
ANI	O
,	O
and	O
stored	O
the	O
calling	O
equipment	O
number	O
in	O
reed	B-Algorithm
relay	I-Algorithm
packs	O
in	O
the	O
sender	O
.	O
</s>
<s>
When	O
queried	O
,	O
AMAT	O
sent	O
a	O
high-current	O
pulse	O
through	O
the	O
wire	O
for	O
that	O
particular	O
line	O
,	O
inducing	O
pulses	O
in	O
the	O
appropriate	O
rings	O
which	O
were	O
amplified	O
by	O
a	O
cold	O
cathode	O
tube	O
amplifier	O
and	O
then	O
by	O
a	O
relay	O
,	O
and	O
sent	O
back	O
to	O
the	O
transverter	O
which	O
supplied	O
it	O
to	O
the	O
sender	O
for	O
transmission	O
by	O
ANI	O
to	O
the	O
tandem	B-Device
office	I-Device
.	O
</s>
<s>
Stored	B-Device
program	I-Device
control	I-Device
exchanges	I-Device
,	O
having	O
computers	O
anyway	O
,	O
do	O
not	O
need	O
separate	O
AMA	O
equipment	O
.	O
</s>
<s>
The	O
BAFAG	O
uses	O
the	O
GR-1100	O
(	O
Billing	O
Automatic	B-Application
Message	I-Application
Accounting	I-Application
Format	O
,	O
BAF	O
)	O
specification	O
to	O
record	O
call	O
history	O
.	O
</s>
<s>
The	O
members	O
of	O
the	O
3rd	O
Generation	O
Partnership	O
Project	O
(	O
3GPP	O
)	O
have	O
been	O
working	O
toward	O
Abstract	B-Protocol
Syntax	I-Protocol
Notation	I-Protocol
One	I-Protocol
(	O
ASN.1	B-Protocol
)	O
-encoded	O
Charging	O
Data	O
Records	O
(	O
CDRs	O
)	O
to	O
be	O
mapped	O
to	O
the	O
AMA	O
records	O
in	O
BAF	O
.	O
</s>
