Configuring PAD/ATPAD Ports 59
ATPAD Ports
Flow Control
You can configure the ATPAD for either type of flow control:
• Control Signal
• XON/XOFF
If you select Control Signal, the port does not send data if the port's Pin 14 input is
LOW. If the port wants to flow control the attached device, it sets its CTS output
LOW.
If you configure the port for XON/XOFF, the port stops sending data if it receives
the configured XOFF character. It resumes transmission when it receives an XON
character. You can configure the XOFF and XON characters. If the port wants to
flow control the attached device, it sends an XOFF character. Then it sends an XON
character when it is ready to receive more data.
Caution!
If the port's message queue overruns because flow control is not in effect, the port
discards data and this alarm is generated:
Pn - DATA DISCARDED
where: Pn - is the port identifier, and n is the port number.
Protocol Identifier
You can use a Protocol Identifier to ensure that only calls from other devices using
the same Protocol Identifier are accepted.
You configure a Protocol ID in the port record. The PID is inserted in the Call User
Data field of all Call Request packets generated by the port. All incoming Call
requests are checked for the presence of the same PID. If it is not present in the Call
Request packet, the call is rejected.
If you leave the Protocol ID parameter blank, no PID is inserted in Call Requests,
and there is no checking of incoming Call Request PIDs.
CUD and Facilities
Call User Data (CUD) and facilities in incoming Call Request packets are ignored
except for the PID. If you need to insert CUD and Facility fields in Call Request
packets generated by the port, do this:
Step Action
1
Configure one of the Stored Addresses using the X.28 Call Command
format.
2
Insert the appropriate CUD and Facilities fields in the configured Call
Command string.
3
Use the ATDSn command referencing the correct Stored Address.
