Verilink HDM 2182 (880-502925-001) Product Manual - Manual (Page 11)

HDM 2182 DS3 DSU Overview
Verilink HDM 2182 User Manual
1-3
Inband
Management
Channel
Specialized support is provided for the inband management
channel in C-bit parity applications. The three C-bits in M-subframe
5 of the DS3 frame are assigned as a 28.2 kbit/s terminal-to-
terminal path maintenance data link. The signal format used on
this data link consists of messages using the Link Access Procedure
on the D-channel (LAPD) protocol. A dedicated HDLC controller is
built into the hardware for this 28.2 kbit/s LAPD data link. The
controller supports polled, interrupt-driven operation.
Far-End Alarm
and Control
Dedicated support is provided for Far End Alarm and Control
(FEAC) signals in C-bit parity applications. The third C-bit in M-
subframe 1 of the DS3 frame provides the FEAC signal. A bit-
oriented message protocol (16 bit length) is used on the FEAC data
stream.
Downloadable
Upgrades
As a member of the AS2000 product family, the HDM 2182
incorporates Verilink’s Advanced Programmable Architecture
(APA).
With APA, you can download upgraded firmware to all HDM
modules on your shelves from a single NCM source into the
modules’ onboard RAM via FTP. The firmware contained in the
flash can also be field-replaced with upgraded chips.
Compatibility
with Other
Verilink Products
The HDM 2182 can reside on the same shelf with all other AS2000
products; however, it does not pass data on the midplane and does
not use the TABS bus of the shelf midplane. The HDM 2182 is a
standalone system that can also be managed through the ACP bus
of the shelf midplane by an NCM 2000 module. Advantages of using
the NCM module include:
•
Higher security on the network with four levels of access using
password control (instead of only one access password).
•
Verilink’s proprietary overhead bandwidth signalling that
enables you to configure and troubleshoot the far-end node
without interference from repeaters in the network. (This
overhead bandwidth requires the C-bit parity format.)
•
Up to three users can access the module at a time.
•
Using the Advanced Programmable Architecture (APA) to
download upgrade firmware to all HDM 2182 modules within
or cross-shelf from a single NCM source.