HP J3138A, Installation Manual

Page: 22 / 104

2-6
Installing the HP AdvanceStack Internet Router
Preparing to Connect to a Network
In
st
all
a
ti
on
Balanced drivers allow EIA/TIA-449 signals to travel greater distances than
the EIA/TIA-232 signals. Table 2-4 lists the maximum speeds and distances for
EIA/TIA-449, which are also valid for V.35, X.21, and EIA-530 signals.
Table 2-4. EIA/TIA-449, V.35, X.21, and EIA-530 Speed and Distance Limitations
C A U T I O N
The EIA/TIA-449 and V.35 interfaces support data rates up to 2.048 Mbps.
Exceeding this maximum could result in loss of data and is not recommended.
Console and Auxiliary Port Considerations
All router models include an asynchronous serial console and auxiliary port.
The console and auxiliary ports provide access to the router either locally
(with a console terminal) or remotely (with a modem). This section discusses
important cabling information to consider before connecting a console
terminal (an ASCII terminal or PC running terminal emulation software) to
the console port or modem to the auxiliary port.
The main difference between the console and auxiliary ports is that the
auxiliary port supports hardware flow control and the console port does not.
Flow control paces the transmission of data between sending device and a
receiving device. Flow control ensures that the receiving device can absorb
the data sent to it before the sending device sends more. When the buffers on
the receiving device are full, a signal is sent to the sending device to suspend
transmission until the data in the buffers has been processed. Because the
auxiliary port supports flow control, it is ideally suited for use with the high-
speed transmissions of a modem. Console terminals transmit at slower speeds
than modems; therefore, the console port is ideally suited for use with console
terminals.
Data Rate (Baud) Distance (Feet) Distance (Meters)
2400 4100 1250
4800 2050 625
9600 1025 312
19200 513 156
38400 256 78
56000 102 31
154400 (T1) 50 15