User`s guide

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Configuration - Network > Legacy Protocols TPAD
TPAD is a simplified version of the X.25 PAD specification that is commonly used for carrying
out credit-card clearance transactions. Digi units support the use of TPAD over:
ISDN B and D-channels
TCP
UDP
SSL
XoT
Automatic back-up between any two of these “layer 2 interfaces” or “transport protocols” is
supported.
For further information on using TPAD please refer to Digi technical support and ask for a
copy of “TG2 - Introduction to TPAD and X.25”.
Configuration - Network > Legacy Protocols TPAD n
Use TPAD over interface
This section is used to select whether the TPAD instance will use ISDN B-channel X.25,
ISDN D-channel X.25, TCP, VXN or SSL as the transport protocol. For ISDN D-channel
operation, ensure that the “LAPD” option is selected. For ISDN B-channel operation or
operation through a synchronous port, select “LAPB”. In the case of LAPB and LAPD it is also
possible to specify an interface number. This parameter specifies which LAPB or LAPD
instance to use for the relevant TPAD instance. Select “0” or “1” for LAPB or “0” or “1” for
LAPD. When using LAPB with ISDN this parameter may be set to “255”, which means use
any free LAPB instance. This is useful when more than 2 POS terminals are connected to the
router and the acquirer does not support multiple Switched Virtual Circuits (SVCs) on a
single B-Channel. A value of 254 will use an available LAPB instance but will use the same
ISDN B channel if two calls are attempted to the same ISDN number at the same time. (All
services that the POS terminals may dial must support multiple SVCs if using the setting
254.)
Use backup interface
This section is used to specify a backup interface that will be used automatically if the call to
the primary interface fails. Note that the primary interface will be tried first for every new
call attempt.
Configuration - Network > Legacy Protocols TPAD n > ISDN settings
Use number x to make outgoing ISDN calls
This parameter may be used to specify an ISDN number. This is used in cases where no
ISDN number is provided with the ATD command when making an outgoing call.
Use prefix x
This parameter is used to specify a dialling code that the unit will place in front of the
telephonenumber that is issued by the terminal in the ATD command. For example, if the
Prefix # was set to 0800 and the number specified by the terminal in the ATD command
was 123456, the actual number dialled by the unit would be 0800123456.
Remove prefix x from number in ATD command
This parameter is used to specify a dialling prefix that is normally inserted by the terminal in
the ATD command that is removed by the unit before dialling takes place. For example, if
the Prefix removal # was set to 0800 and the terminal issued an ATD command containing
0800123456 then the actual number dialled by the unit would be 123456.