Tia/Eia-232C (Rs-232C); Ethernet (100Base-Tx) - Comtech EF Data UT-4500 Series Installation And Operation Manual

UT-4500 Series C- and Ku-Band Up Converters
Serial Interface Operation
communication, there are two separate, isolated, independent, differential-
mode twisted pairs, each handling serial data in different directions.
It is assumed that a 'Controller' device (a PC or dumb terminal) transmits data in
a broadcast mode via one of the pairs. Many 'Target' devices are connected to
this pair, and all simultaneously receive data from the Controller. The Controller
is the only device with a line-driver connected to this pair; the Target devices
have only line-receivers connected.
In the other direction: On the other pair, each Target has a Tri-state line driver
connected; the Controller has a line-receiver connected. All the line drivers are
held in high-impedance mode until one – and only one – Target transmits back to
the Controller. Each Target has a unique address; each time the Controller
transmits, the address of the intended recipient Target is included in a framed
'packet' of data. All of the Targets receive the packet, but only one (the
intended) replies. The Target enables its output line driver and transmits its
return data packet back to the Controller in the other direction on the physically
separate pair.
To summarize EIA-485 (Full Duplex) operation:
• Two differential pairs – one pair for Controller-to-Target, one pair for Target-
to-Controller.
o Controller-to-Target pair has one line driver (Controller), and all
Targets have line-receivers.
o Target-to-Controller pair has one line receiver (Controller), and all
Targets have Tri-state drivers.
8.2.2

TIA/EIA-232C (RS-232C)

This is a much simpler configuration in which you directly connect the Controller
device to the Target via a two-wire-plus-ground connection. One conductor
carries Controller-to-Target data via EIA-232C electrical levels, while the other
conductor carries Target-to-Controller data in the other direction.
8.2.3

Ethernet (100BASE-TX)

The unit implements a Telnet server that accepts Telnet terminal connections
using Transmission Control Protocol (TCP) on port 23. After you enter the
8–2
MN/UT4500.IOM
Revision 3