Chapter 1 Overview
Hardware Architecture
1-6
TA 102/202 Technical Support Guide
High Speed Data Interfaces
The TA 102/202 eMTA is versatile in that it offers two methods for connecting a
subscriber PC to a CATV cable. There is a USB connection and an Ethernet connection.
Only one connection (Ethernet or USB) is permitted.
Ethernet Interface
For an Ethernet connection, the point of connection between a subscriber PC and the TA
102/202 eMTA is the Ethernet Interface. The Ethernet Interface consists of a standard
10Base-T RJ-45 Ethernet connector, voltage suppressors, a 10Base-T LAN single port
transformer module, and a universal Ethernet interface adapter.
The Ethernet Interface can support up 32 concurrent Ethernet devices (hosts) on the
internal LAN side, each one with its own IP and MAC address. Note that the interface is
fully compliant with the IEEE 802.3 specification and operates in full-duplex mode.
Additionally, the TA 102/202 eMTA Ethernet Interface can be configured so it can filter
packets that are not IP or ARP based.
USB Interface
For a USB connection, the point of connection for a subscriber PC and the TA 102/202
eMTA is the USB Interface. The USB Interface provides the physical interface to the
USB cable and consists of a standard USB connector, USB port transient voltage
suppressors, a switching current source, and associated components. In other words, it
has all the control circuitry and line drivers to support 12 Mbps operation, including the
CM USB Communications 1.1 Class Driver.
POTS Interface
For a POTS (Plain Old Telephone System) connection to a telephone the TA 102/202
eMTA provides a POTS Interface. The POTS interface consists of two Subscriber Line
Interface Circuits (see Figure 1-3) that provide two telephony line interfaces for twisted
pair connections. The Subscriber Line Interface Circuits (SLIC) provide the following:
•
Line Feed, to provide power to a phone even during power outages.
•
Overload Protection, so a lightning strike doesn’t blow up the MTA.
•
Ringing, so you know when someone’s calling.
•
Signaling, to detect when the receiver is off the hook and what number you dial.
•
Coding, to convert analog signals to digital signals and vice versa.
Each line supports a loop length of at least one hundred and fifty(150) meters, providing
a loop line voltage of 48 VDC. Note also that each line can have its own phone number
and they can be used simultaneously. Both line interfaces support the administrative
coupling of multiple subscriber numbers to a single line.
