3060/X21
109001UA
P
ATTON
E
LECTRONICS
C
O
.
I
NSTALLATION
A
ND
O
PERATIONS
M
ANUAL
1-3
Operation
Channel Selection Modes
The Patton 3060/X21 (CTS MD-X.21/TCB) provides two selectable sub-channel service
modes of operation, the Scanning Mode and Priority Mode. Depending on system
requirements, either mode may be selected by internal dip switch settings. Both modes switch
on activity from the sub-channel. Activity is defined as raising Control on a sub-channel
configured as a DCE, raising Indicate on a sub-channel configured as a DTE or data
transitions while in the switch on data mode.
Scanning Mode - In the Scanning Mode the Patton 3060/X21 (CTS MD-X.21/TCB) scans
each Sub-Channel, in sequence, beginning with Sub-Channel 1. This rotational sequence is
repeated continually with each attached Sub-Channel having equal access to the
communications link. When data or control lines from a sub-channel become active that Sub-
Channel is switched through to the master port by the 3060/X21 (CTS MD-X.21/TCB). All
remaining Sub-Channels are locked out until the first device becomes inactive. When the Sub-
Channel device becomes inactive, the 3060/X21 (CTS MD-X.21/TCB) will resume scanning
the sub-channels for another active signal.
Priority Mode - When configured for Priority Mode operation, the Patton 3060/X21 (CTS MD-
X.21/TCB) monitors all Sub-Channels simultaneously with Sub-Channel 1 having the highest
priority. When a sub-channel becomes inactive, the 3060/X21 (CTS MD-X.21/TCB) will
automatically default to the highest priority (lowest number) Sub-Channel with activity.
Contention - Contention for the Master port is accomplished by asserting C (Control) if the
Sub-Port is configured as a DCE, I (Indicate) if the Sub-Port is configured as a DTE or Data
Transitions from the attached Sub-Channel devices in either configuration. The active
interface lead, C or I, as well as selection of contention mode,
“Data Transitions” or “Interface
Lead” activation, can be selected on an individual basis for each Sub-Channel. Once a Sub-
Channel asserts an active control signal the control signal will be passed through to the Master
Port, depending on DTE / DCE configuration of the Sub-Channel and Master Port. This
control will be passed without delays. If the Master Port is configured as a DTE the signal will
be passed as C. The I returned from the Master will have an optional delay added before the
signal is returned to the Sub-Channel port.
Channel Tail Circuits
A buffer is built into the unit for tail circuit (DCE to DCE) applications. An 8 bit centered ring
buffer is used to correct the clock phasing errors generated between the Modem on the
Master Port and the Sub-Channel port for the data transferred from the Sub-Channel to the
Master Port. If the unit is operated in an asynchronous environment the buffer must be
bypassed. This is accomplished by moving the SYNC/ASYNC switch.
