RFL Electronics IMUX 2000 - Physical Slots and Time Slots

Because RFL™ and Hubbell® have a policy of continuous product improvement, we reserve the right to change designs and specifications without notice.
3.4 PHYSICAL SLOTS AND TIME SLOTS
As discussed above, a given channel module (depending on its function) may use one or more of the
twenty-four 64-Kbps time slots provided by each direction of a T1 circuit. In addition, a given channel
module may be assigned to any available time slot (or group of time slots) within a T1 circuit,
regardless of its physical location (slot) on an IMUX 2000 M-DACS equipment shelf. This makes it
important to distinguish physical slots on IMUX 2000 M-DACS multiplexer shelves from time slots
within the T1 circuit. In most cases, they are not directly related.
3.4.1 CHANNEL DIRECTION AND RELATIONSHIP TO CM4 MODE
Channel modules can be set to transmit in either "Direction A" or "Direction B". The transmit and
receive directions are always opposite from one another. This means that a channel module set to
transmit in Direction A will receive from Direction B. If the channel module is set to transmit in
Direction B, it will receive from Direction A. Every channel module has a switch that sets its
transmit/receive direction. Consult the Instruction Data Sheets in Sections 11 through 16 of this
manual to determine the location and labeling of this switch on any given module.
Unless specifically indicated in the module data sheet, the receive direction is selected automatically
based on the chosen transmit direction.
Each CM4 Common Module operates in one of two modes: DI-A or DI-B. CM4 modules operating in
the DI-A mode take the transmit data from channel modules set to transmit in Direction A, and
multiplex it together for transmission on the outgoing T1 port 5 of the DACS module. CM4 modules
operating in the DI-B mode take the transmit data from channel modules set to transmit in Direction B,
and multiplex it together for transmission on the outgoing T1 port 6 of the DACS module.
Figure 3-8 illustrates this process. Channel modules can be set to transmit in either direction. The
channel modules set to transmit in Direction A and receive from Direction B (DACS module port 5)
will work according to Figure 3-8a; Figure 3-8b shows how the channel modules set to transmit in
Direction B and receive from Direction A (DACS module port 6) will work.
Note the "CTL" connection on Figure 3-8. This is a control wire. When a channel module set to time
slot N is active in a drop/insert multiplexer, the control wire carries a signal that tells the CM4 to place
local data (from the channel module) instead of through data (from the incoming T1 signal) into time
slot N of the outgoing T1 signal.
M-DACS-T1 RFL Electronics Inc.
October 25, 2004 3-11 (973) 334-3100