Multi-Tech Systems 92U04A22760 ユーザーズマニュアル

Chapter 3 - Troubleshooting

If the modem
returns …

Then ask … 

Action

no carrier(esp. for
data communi-
cation)

Is the selected
bearer type
supported by the
called party?

Is the selected
bearer type
supported by the
network?

Type AT+CEER to view the extended error
code (see “Interpretation of Extended Error
Codes” table, page 20).

Be sure that the selected bearer type is
supported by the called party.

Be sure that the selected bearer type is
supported by the network.

If no success, try bearer selection type:
AT+CBST=0,0,3

If the modem
returns

Then ask … 

Action

no carrier
(esp. for  voice
communi-cation)

Be sure that the semicolon character (“;”) is

typed immediately after the phone number in
the AT command. E.g., ATD######;

type AT+CBST=0,0,3

Is the received
signal strong
enough?

See “Signal Strength Verification”. 

Is the antenna
properly
connected?

See “Antenna/RF Specifications”.