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Siemens TC35T GSM Digital Transceiver
16
to ring but instead immediately responds with a result code 3 (‘no carrier
detected’), or if the LED continues to flash, it is likely that:
•
It has not been registered properly on a GSM network — see the Siemens
TC35T user’s manual and notes above.
If the TC35T has definitely been registered on the GSM network,
check that the registration is for ‘non-transparent use’.
or
•
It is not fitted with a SIM or the SIM is not enabled (check with your provider)
or
•
The SIM is programmed to require a PIN to be entered every time it is turned
on.
This is often the case with newly supplied SIMs.
We strongly
recommend that this feature is disabled; this is best done using a GSM phone
(please refer to your SIM provider for more information).
Please refer to Appendix A if you can only access a network where
use of a PIN is a legal obligation with the airtime provider.
•
The power supply is inadequate, e.g. it cannot supply the high surge currents
during transmission. (See Section 3, ‘Power Supply’.)
Once communication is established with a datalogger via the TC35T, it is essential
to monitor how error-free the communications link is. PC208W generates log files
which indicate the number of attempts required to retrieve good data (‘retries’).
While the chances of getting bad data stored to disk are very small (because of the
error checking protocols used) the speed at which data is collected can fall
markedly if the link is very noisy. This will lead to much higher phone charges. If
many retries are recorded it is worth checking the signal strength, studying the
antenna position and the likely causes of interference.
If you still encounter problems it is also worth checking the firmware version of
the TC35T module. Campbell Scientific has validated use with units with firmware
revision: “3.00” (checked using instruction
ATI
). While later software revisions
will probably be backwards compatible, older software may not work so well.
Please contact your supplier for an upgrade if necessary.
8.2 The Base Station Fails to Get a Response from the Datalogger
Check the following points:
•
Is the TC35T configured to ignore hardware handshaking (see Section 6.3)?
•
Have you ensured that your base station modem setup includes commands to
switch off flow control from the base station?
•
Are you powering the TC35T on and off periodically?
•
The datalogger program which is controlling the power of the TC35T is either
wrong, or is not running (perhaps due to a low battery voltage).
•
the number you are dialling is the voice number for the SIM rather than the
data number - if you get "deadline" when the TC35T is on or an
"answerphone" service when it is turned off this is almost certainly the
problem.
NOTE
NOTE