Visara FEP-4600 Installation - Manual (Page 88)

Chapter 7. SDLC Interface
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Line Protocol: This option allows you to select between SDLC and X.25. For a
description of configuring the X.25 interface see the chapter on X.25.
Line ID: This is a text field (alphanumeric plus underscore, dash, and period) that you
can enter a description for the line to make it more recognizable for management
purposes.
Line Speed: Most lines will be configured for ‘External’, indicating that a modem or
modem eliminator is to be attached that will provide the clocking for the circuit. If no
modem or modem eliminator are to be used, then you will need to set this option to one
of the clocking speeds provided in the drop down. The QSA card provides the clocking
signal for SDLC interfaces. This option is normally used in coordination with using a
DCE cable for direct attachment to the platform that the FEP-4600 is communicating
with. Supported clocking speeds are:
• 4800 bps
• 9600 bps
• 14,400 bps
• 19,200 bps
• 56,000 bps
• 64,000 bps
• 128,000 bps
• T1 (1.544 Mbps) speed
• E1 (2.0 Mbps) speed
Duplex: There are three values for this option:
• Full – RTS is kept active to reduce turnaround time. If you are connected to a 2-
wire circuit, you must not use this setting.
When using this for multi-drop lines, the FEP-4600 does not have to wait for a
response from one drop before a poll is sent to the next drop in the list. The
secondary PUs on the line should be set for Half Duplex. Outbound data takes
priority over polling a drop with no outbound data.
When using this on point-to-point lines, both the FEP-4600 and the secondary
station can be set for Full Duplex
• Half – RTS is switched. The FEP-4600 and the secondary PU(s) take turns
communicating over the line.
For multi-drop lines, each drop is polled in order, regardless of whether there is
outbound data for one of the drops.
• HDXSP – If the FEP-4600 has outbound data, sending the data will take
precedence over a scheduled poll to a drop.
Note: If you are having trouble getting a new circuit up, then set this value to ‘Half’ until
you resolve what is causing the problem. You should also turn off all but one drop on a
multi-drop line, and add more drops one at a time until they all work. If adding a drop
causes problems, check to ensure that the drop is configured to run in Half Duplex mode.