Ethernet Interfaces; Basic Rate Isdn Interfaces - Allied Telesis AT-AR020 PRI E1/T1 Hardware Reference Manual

Hardware Reference
C613-03023-00 REV J
The transition cable does more than simply change the physical connector. The
switch or router hardware reads the cable type from the AMPLIMITE plug and
enables or disables the internal driver electronics as required. To function
correctly, the cables must be identical to the cables described in
Loopback Plugs for PICs" on page
The DCE cable type reverses the direction of the data lines as well as the clock
lines. This cable is intended to be used when the switch or router supplies the
clock for the attached device. This is commonly used when the switch or router
is connected to the synchronous interface of another device or a host, without
using an intermediate modem or NTU (Network Terminating Unit). Therefore,
the DCE cable must only be connected to a switch or router interface that is set
to generate the clock. The Interfaces chapter of the Software Reference or
Reference Manual for your switch or router has more information.
The transition cable can be changed at any time. It is not necessary to power-
down the switch.
When an RS-232 DCE transition cable is connected to a synchronous interface
configured to generate clocks, the maximum clock speed is 38400 bps. When an
X.21 DCE or V.35 DCE transition cable is connected to a synchronous interface
configured to generate clocks, the maximum clock speed is 2 Mbps.

Ethernet Interfaces

Dual 10BASE-T/AUI Interfaces
The AT-AR022 ETH PIC has a dual 10BASE-T/AUI Ethernet interface. Only
one Ethernet interface type can be active at any one time. The PIC auto-senses
which Ethernet interface type is in use.
For performance reasons, the AT-AR022 PIC is not recommended for use in the
AT-AR040 NSM. When the AT-AR040 NSM is installed in a switch or switching
router, Ethernet connections should be made through the Ethernet ports. When
the AT-AR040 NSM is installed in a router, AT-AR022 PICs should be installed
in base-unit (router) PIC bays.
10Base-T/100Base-TX Interfaces
The AT-AR026 4ETH PIC has four 10BASE-T/100BASE-TX ports with RJ-45
connectors. Port characteristics such as speed, flow control, half/full duplex,
and auto-negotiation can be set by configuring links on the PIC's PCB. See
"AT-AR026 4ETH PIC" on page 12

Basic Rate ISDN Interfaces

The AT-AR021(S) BRI-S/T and AT-AR021(U) PICs provide Basic Rate ISDN
(BRI) interfaces. In both cases the connecter type is RJ-45. The interfaces
support two 64K B channels and one D channel.
For the AT-AR021(S) BRI-S/T PIC, the operational mode of the BRI ISDN
interface (TE or NT) is determined by jumpers mounted on its board. See
"AT-AR021(S) BRI-S/T PIC" on page 7
The AT-AR021(U) PIC only supports TE mode. The Integrated Services Digital
Network (ISDN) chapter of the Software Reference or Reference Manual for
29.
for more information.
for locations and names of the jumpers.
19
"Cables and