Trouble
Shooting
I(
you have problems, the most likely cause is the phone line. Noise on the
line or a weak phone line signal can often result in lost or invalid data.
Try
to
re-dial the call to insure that the connection is noise-free and there
is
no
interference.
If
communication still can not be established and the TELEPHONE
INTERFACE II checks out in the TEST mode, refer
to
the chart below.
Symptom Problem/Solution
READY LED is off
Is power
"on"?
Is handset properly positioned in
rubber cushions (cord toward RS-232-C
cable end)?
Are mode switches set properly?
1.
When communicating with time-share
computer, modem must be in Originate
mode.
2.
When communicating with another
TRS-80, mode selection must be agreed
upon before data transmission. (One
modem must be
in
Answer mode and
other in Originate mode.)
3.
For data communication, duplex switch
must be in either Full
or
Half position (not
TEST).
4.
Is modem at the other end compatible
with the TELEPHONE INTERFACE II?
(See specs.) Remote modem should
be
either another TELEPHONE INTERFACE
II, a Bell
103
or
equivalent.
Communication can not
be
established
with a Bell 202 type.
Double Character
Is system
in
half-duplex mode?
Display
I(
remote computer echoes all
characters, the TRS-80 system must
be in the Full-duplex mode.
I(
communication system is half-
duplex (no echo), either RS-232-C
or TELEPHONE INTERFACE II (not
both) must be
in
half-duplex.
8
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