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2. Introduction
2.1 Functional Description
The Stat-4, Stat-8, and Stat-24 are advanced, full-function compact statistical multiplexors. They’re capable of
multiplexing asynchronous data sub-channels at data rates of 75 to 38,400 bps onto a single composite
synchronous channel operating at up to 19,200 bps. The Stat-4 has four sub-channels, the Stat-8 has eight
sub-channels, and the Stat-24 has 24 sub-channels. An external clock signal automatically determines the
composite channel rate, and you select sub-channel characteristics and other system features via configuration
menus. All units are available in desktop versions, which also install in 19" racks with rack adapter kits.
The Stat-4, Stat-8, and Stat-24 use a dynamic data buffer management technique to allocate available buffer
capacity according to sub-channel activity. Error-free end-to-end data transmission is ensured by powerful and
efficient error detection and automatic retransmission, completely transparent to the user.
The muxes provide independent hardware and software flow control for each sub-channel, both end-to-end
flow control (DTE to DTE) and terminal flow control (DCE to DTE). For compatibility with most applications,
choose from among several software flow-control characters.
The Stat-4, Stat-8, and Stat-24 permit full system configuration (including configuration downloading from the
local stat mux to the remote stat mux, and vice-versa) from any sub-channel port. The stat mux uses a password
to prevent unauthorized configuration changes.
You can configure the mux with any standard cathode-ray terminal (CRT), using a simple, menu-driven facility.
Configuration parameters are stored in non-volatile memory and are immediately available upon power-up.
To facilitate initial system configuration, the multiplexors store—in addition to the user-selected
configuration—a set of default configuration parameters (factory setting), that you can select via a jumper, to
provide a common starting point for any stat mux.
The Stat-4, Stat-8, and Stat-24 have comprehensive diagnostics functions, including automatic self-test upon
power-on, local and remote sub-channel loopback, and local and remote composite channel loopback. Front-
panel indicators show the condition of each sub-channel and composite link synchronization status. In
addition, the muxes control the V.54 pins (pins 18 and 21) of the RS-232 interface serving the composite link,
thereby allowing control of analog and remote digital loopback functions of the modem connected to the stat
mux.
2.2 Available Models
The following models are available:
Model Number
Name
Ports
MX864A
Stat-4
(4) RJ-45, (1) DB25
MX866A
Stat-8
(8) RJ-45, (1) DB25
MX868A
Stat-24
(24) RJ-45, (1) DB25
CHAPTER 2: Introduction
