User's Manual

UMAC Turbo CPU/Communications Board Hardware Manual
Connections 10
USB Type B Receptacle
This connector is used in conjunction with USB A-B cable which can be purchased from any local
computer store. The A connector is connected to a PC or Hub device; the B connector plugs into the
UMAC Turbo CPU/Communications Board. The picture below displays what the two ends on the cable
should look like.
This connector is used to communicate with the host PC through a USB connection. In addition, this
connector is used to install and upgrade the micro-controller Ethernet firmware and to program the static
Internet Protocol (IP) address into an EEPROM that is read on startup. Do not attach a cable to this
connector when communicating to the board via Ethernet.
The maximum cable length according to the USB Specification 2.0 for a full speed cable is 5 m (~15ft).
According to the USB specification, up to five USB cables can be connected together with a hub, to
create a maximum length of 30 m (~98ft). In addition, to extend the length of the USB connection there
are USB active extension cables available. Use a USB cable of high quality. Using higher quality USB
cables, some systems have operated up to 10 m (30ft) cables without the use of an active extension cable
or hub. However, violating the specification by running a cable more than 5m is not recommended or
guaranteed.
J6: Ethernet RJ45 Connector
This connector is used for Ethernet communications from the UMAC to a PC. The appropriate Category
5 10/100-Base T network cable that mates to this connector can be purchased from any local computer
store. The type of network cable to purchase depends on the configuration to the host PC.
When making a direct connection to a Host communication Ethernet card in a PC, a Category 5
networking crossover cable must be used. A standard Category 5 straight through networking cable
cannot be used in this scenario. See left section of the following diagram.
When using a connection to a network Hub or switch, the standard Category 5 straight through
networking cable must be used, and not a crossover cable. See right section of the figure below.
Performance can be degraded by the use of a hub or switch. Network hubs or the more intelligent
network switches have processors inside them which can add delays of at least 15 msec to the UMAC
communications.