Radio Shack Modem I TRS-80 Owner's Manual page 4

Installation
Modem/Telephone Connection
Figure
1
shows
the
connection of a
Modem
I
to
telephone lines
using the
new
modular
connectors. If
your telephone has
this
type of connection, attach
your
Modem
I
as
shown.
If
your telephone has
the older
style
four-prong connection (see
Figure
2),
you
will
need an
adapter
which allows
the
Modem
I
to
be used
in parallel
with
your
telephone.
Radio Shack
sells this
type of adapter, Cat.
No. 279-360.
If
your telephone
is
wired directly to the wall as
in
Figure
3,
you must
contact
the
telephone
company and have
them
install
modular connections.
Be
aware
however,
that
you
will
be charged
for this
service.
After
connecting
the
telephone,
make
sure
that
the
mode
switch
on
the
Modem
is
off.
Your
telephone should be operating normally now.
AC
Connection
Connect
the
ac
adapter
to
the
ac
jack
on
the
Modem's
rear
panel and
to
an
electrical
wall outlet.
Note:
Use only
the supplied, UL-listed adapter.
The
use of
any other adapter
could
damage
the
Modem.
Modem/Computer
Connection
via
RS-232-C
Interface
For
most
applications,
you
will
use an
rs-232-c
equipped computer. Table
1
summarizes
the
cable
and connection requirements for rs-232~c
equipped
trs-80's.
Using
the table, select
the appropriate
connector for
your computer.
Connect
the
computer's rs-232-c interface
to
the specified
connection point
on
the
Modem.
TRS-80 Model Cable
Connection Point
TRS-80
Modem
I
Model
1,
Level
II
26-1145*
Card-Edge
on
Exp/Int
DB-25
"RS232C"
Model
II
26-4403
DB-25
"CHANNEL
A/B"
DB-25
"RS232C"
Model
III
26-1408
DB-25
Serial I/O
DB-25
Color
Computer
26-3014
DIN
Serial I/O
DIN
"RS232/CASS"
This
is
the
RS-232-C
interface
board.
The
cable
is
included.
Table
1.
RS-232-C Cable
Identification
and Connection