Category : Communication (modem) tools and utilities
Archive   : SP144MAN.ZIP
Filename : APF.TXT

 
Output of file : APF.TXT contained in archive : SP144MAN.ZIP
SPORTSTER 14,400
APPENDIX F. MODEM TESTING


Modem testing is available with the &T
command and Register S16 (Dial test).
All loopback testing conforms to CCITT
Recommendation V.54.
NOTE: Only one test can be performed at
a given time. If you send a test
command while the modem is in test mode,
you'll receive an ERROR message.

TESTING WITH &T

The tests supported through the &T
command include analog loopback, digital
loopback and remote digital loopback.
You can key in your own data during
testing, or use the modem's internal
test pattern and error detector.
In all cases, disable error control
before testing. If the modem is
detecting errors and retransmitting the
affected data, your test results will be
invalid.

Ending a Test_&T0, S18

Issuing the &T0 command terminates a
test. Alternatively, set Register S18
to a specified number of seconds, for
example, S18=10. When the 10 seconds
are up, the modem automatically ends the
test and returns to Command mode. If
the test was Analog Loopback, the &T0
command hangs the modem up. If the test
was Digital or Remote Digital Loopback,
issue an ATH command to hang up the
modem, or an ATZ command to hang up the
modem and reset it to its defaults.
NOTE: If you use the S18 test timer,
but in the process of testing you issue
an ATZ command, S18 resets to zero and
the timer is disabled. Also, you cannot
store a value for S18 in nonvolatile mem
ory: its power-on and reset default is
always zero.
Analog Loopback_&T1, &T8

This test checks the operation of the
modem's transmitter and receiver. Data
flow is shown in Figure F.1. Modem/DTE
indicates the modem's interface with
the computer (Data Terminal Equipment).


Figure F.1_Data Flow During Analog Loopback

There are two analog loopback options.
The first, &T1, involves your typing
data that you can verify at your screen.
The second option, &T8, is an internal
self-test that does not involve the
keyboard or screen. It isolates the
modem from the computer interface to
give you a more specific result.
&T1
1.The modem should be on hook in
Command mode. If you wish, set
Register S18 as a test timer. For
example, insert S18=10 in the
following command string before &T1.
AT &M0 S18=1 &T1
The modem disables error control,
sets the timer, enters analog
loopback (AL) mode, and sends a
CONNECT message.
2.Type recognizable data so that you
can verify it when it is looped back
to the screen.
3.End the test. If you set S18, the
modem automatically stops the test at
the timeout, exits AL mode and
responds OK.
If you didn't set Register S18, wait
one second and type +++ to end the
test and return the modem to Command
mode. When the modem responds OK,
type AT&T0 to terminate AL mode and
hang up the modem. (Typing ATH has
the same effect. Typing ATZ also has
the same effect, but also resets the
modem and restores your &M default.)
The modem responds OK. If the modem
sends an ERROR message, you have
issued an invalid command.
4.If there were no errors, reset the
modem to &M4, for error control,
unless you've issued the ATZ reset
command.
NOTE: If the modem is in Online-
Command mode, that is, still
connected to a remote modem, and you
send it an &T1 or &T8 command, it
drops the call, enters AL mode, sends
a CONNECT result and waits for
loopback characters.
&T8
This AL option causes the modem to send
an internal test pattern to its
transmitter and loop it back to the
receiver. An internal error detector
counts any errors and, when the test is
ended, sends the number of errors or 000
(no errors) to the screen.
Since you don't type anything during
this test, and the modem does not send
anything to the screen, this option veri
fies only the modem. If there are no
errors but your problem continues, it
may be at the computer interface.
1.The modem should be on hook in
Command mode. If you wish, set
Register S18 as a test timer. For
example, insert S18=10 in the
following command string before &T8.
AT &M0 S18=10 &T8
The modem disables error control,
sets the timer and enters AL mode.
The modem sends its internal test pat
tern to the transmitter, and loops
the pattern back to the receiver.
You will not see any data on your
screen.
2.End the test. If you set S18, the
modem automatically stops the test at
the timeout. If you didn't set
Register S18, type AT&T0 to end the
test. Or use ATH or the command that
resets the modem, ATZ. Both of the
latter end the test and hang up the
modem.
When the modem hangs up it returns a
three-digit code, followed by OK. A
code of 000 indicates no errors were
found. A code of 255 indicates 255
or more errors. An ERROR message
indicates that you issued an invalid
command.
3.If there were no errors, reset the
modem to &M4 for error control unless
you issued the ATZ command.

&T2

This option is reserved.

Digital Loopback_&T3

If your modem has passed the AL test,
this test can help you locate a problem
with a remote modem or the telephone
channel. Figure F.2 shows the data
flow during Digital Loopback (DL)
testing. Modem/DTE indicates the
modem's interface with the computer
(Data Terminal Equipment).


Figure F.2_Data Flow During Digital Loopback

1.Set the modem to &M0, to disable
error control. Establish a
connection with the remote modem.
2.Bring the modem back to Online-
Command mode with the +++ escape
code. Then send it the AT&T3
command. The modem enters DL mode.
3.The remote user should type a short
message. It will be looped back by
your modem's transmitter for
verification on the remote screen.
You will not see the message or any
other data.
4.When the remote user has completed
the test, issue the AT&T0 command to
end the test. If you wish, return
the modem online (ATO) to resume data
mode. Or type either ATH or the
command that resets the modem, ATZ.
The latter two commands end the test
and hang up the modem. The modem
responds OK. If the modem sends an
ERROR message, you have issued an
invalid command.

&T4, &T5

The &T4 option causes the modem to grant
a remote modem's request for a Remote
Digital Loopback test.
The &T5 option cancels &T4, and the
modem fails to recognize such a request.
This is the default so that your modem
isn't subject to another user calling
and tying up your modem without your
permission.

Remote Digital Loopback_&T6, &T7

This test, like the local digital
loopback test, verifies the condition
of both modems and the phone link.
Data flow is shown in Figure F.3.
Modem/DTE indicates the modem's
interface with the computer (Data
Terminal Equipment).



Figure F.3_Data Flow During Remote Digital
Loopback

The request for and granting of Remote
Digital Loopback testing requires that
both modems use CCITT V.54 standard
signaling. The test must be performed
at 2400 or 1200 bps. If the remote mo
dem does not have the capability or is
not set to respond, you will get an
ERROR result code.
As with Analog Loopback, there are two
Remote Digital Loopback options. If you
select &T6, you send keyboard data to
the modem and verify it when it is
returned over the phone lines and to
your screen. If you select &T7, the
modem sends its internal test pattern
and returns an error count to your
screen.
&T6
1.Set your software to 2400 or 1200
bps. Set the modem to &M0. If you
wish, set the S18 timer.
Establish a connection with the
remote modem. If you haven't already
done so, arrange with the remote user
to cooperate with your testing. The
remote user should set his or her
modem to acknowledge the RDL request,
for example, AT&T4.
2.Bring the modem back to Online-
Command mode with the +++ escape
code. Send it the AT&T6 command.
The modem enters RDL mode.
3.Type a short message. It will be
looped back to your modem by the
remote modem and to your screen for
verification. (The remote user will
not see your data.)
4.End the test. If you set Register
S18 the modem automatically ends the
test when the test timeout is
reached. If you didn't set S18, type
AT&T0 to end the test. If you wish,
return the modem online (ATO) to
resume data mode. Or send either ATH
or the command that resets the modem,
ATZ. The latter two commands end the
test and hang up the modem. The
modem responds OK. If you issue an
invalid command, the modem sends an
ERROR message.
Data errors indicate a problem with
the remote modem or the phone link.
If you have not performed analog loop
back testing with your modem, the
problem may also lie with your modem.
5.Reset the modem to &M4 unless you
used the reset command, ATZ.
&T7
This test option causes the modem to
send an internal test pattern through
the Remote Digital Loopback. An
internal error detector counts any
errors and, when the test is ended,
sends the number of errors or 000 (no
errors) to the screen.
You don't need to type anything during
this test. The modem sends only its
final error count to your screen.
1.Set your software to 2400 or 1200
bps. Set the modem to &M0. If you
wish, set the S18 timer.
Establish a connection with the
remote modem. If you haven't already
done so, arrange with the remote user
to cooperate with your testing. The
remote user should set his or her
modem to acknowledge the RDL request,
for example, AT&T4.
2.Bring the modem back to Online-
Command mode with the +++ escape
code. Then send it the AT&T7
command. The modem enters RDL mode.
The modem sends its internal test
pattern to the remote modem, which
loops it back to your modem. You
will not see the data on your screen.
3.End the test. If you set S18, the
modem automatically stops the test
when the timer times out. If you
didn't set Register S18, type AT&T0
to end the test. After you view the
test results (next paragraph), return
the modem online if you wish (ATO)
and resume data mode. Or send either
ATH or the command that resets the
modem, ATZ. The latter two commands
end the test and hang up the modem.
When you terminate the test, the
modem returns a three-digit code,
followed by OK. A code of 000
indicates no errors were found. A
code of 255 indicates 255 or more
errors. If you issue an invalid
command, the modem sends an ERROR
message.
If you've performed an Analog
Loopback and know your modem is
working properly, errors indicate a
problem with either the phone
connection or the remote modem.
4.Reset the modem to &M4 unless you've
sent it the ATZ reset command.

DIAL TEST_S16=2

The Dial test is used for factory-
testing the frequencies of Touch-Tone
values. When S-Register 16 is set to 2
and a single Touch-Tone is dialed (for
example, ATD7 ), the modem con
tinues to transmit that tone until you
press the Enter key again.



  3 Responses to “Category : Communication (modem) tools and utilities
Archive   : SP144MAN.ZIP
Filename : APF.TXT

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