HBLXT9785HE Cortina Systems Inc, HBLXT9785HE Datasheet - Page 147

• Manufacturer Part Number: HBLXT9785HE
• Manufacturer: Cortina Systems Inc

Specifications of HBLXT9785HE

• Lead Free Status / RoHS Status: Not Compliant

LXT9785/LXT9785E
Datasheet
249241, Revision 11.0
16 April 2007
4.10.3.1
4.10.4
4.11
Figure 29
Cortina Systems
If the link test function is disabled, the LXT9785/LXT9785E transmits to the connection
regardless of detected link pulses. The link test function is disabled by setting Register bit
16.14 = 1.
Link Failure
Link failure occurs if Link Test is enabled and link pulses or packets stop being received. If
this condition occurs, the LXT9785/LXT9785E returns to the auto-negotiation phase if
auto-negotiation is enabled.
Jabber
If a transmission exceeds the jabber timer, the LXT9785/LXT9785E disables the transmit
and loopback functions and the Collision Status bit (Register bit 17.11) is set regardless of
duplex. The jabber timer, according to the IEEE standard, must be between 20 ms to 150
ms. The RMII does not include a Jabber pin, but the MAC may read Register 1 to
determine jabber status. The LXT9785/LXT9785E automatically exits jabber mode after
the unjab time expires. This function is disabled by setting Register bit 16.10 = 1.
DTE Discovery Process
The DTE discovery process is port dependent and must be enabled through software.
The process is implemented as a next page option to the auto-negotiation flow. When the
process is enabled, manual control of auto-negotiation next pages is not allowed. This
feature applies to the LXT9785E transceiver only.
The process depends upon an IP phone, or any other DTE capable of being powered
remotely, having a specific filter that passes NLPs and FLPs. This filter should be non-
polarized to insure that the latest status of Auto-MDIX operation does not effect operation.
This filter attenuates 100 Mbps MLT3 signals and 10 Mbps Manchester-encoded signals,
and must be bypassed when power is applied to the IP phone.
IP telephone system connection.
Typical IP Telephone System Connection
®
LXT9785 and LXT9785E Advanced 8-Port 10/100 Mbps PHY Transceivers
Power
Outlet
Power cable
Generator
UPS/
Powe r
Fa ult
ProCurve Swi tch 2 42 4M
HP J4122B
C o n sole
Mo d u le Sta tu s
Se lf T est
VoIP-Enabled Switch
Reset
1
7
Clear
2 3
8 9 1 0 11 12
4 5 6
13 1 4 15 16 17 18
19
Mod e Se lect
2 0
Act
21
Fd x
22 23 24
100
Li n k
Mode
Li n k
Mode
IP Telephone
1 X
7 X
2X
8X
3X
9X
4X
10 X
5X
11X
6 X
12X
1 2
4 5
7 8
* 8
1 0/100Base-T Ports
3
6
9
#
13X
19X
1 4 X
2 0 X
1 5X
2 1X
1 6X
2 2X
17X
23X
18X
24X
SD
Power and data over
Category 5 cable
Data only over
Category 5 cable
Figure 29
4.11 DTE Discovery Process
Computer
Power cable
shows a typical
Power
Outlet
Page 147