User Guide: Technical Reference SECTION 4 NETWORK MANAGEMENT FOR
ioLink 4
PRELIMINARY
Customer Support (202) 333-7031
4-2
4.2 Configuration
RFC 1406 specifies several configuration parameters for DSX-1 devices. In addition to these, the
ioWave
Management Information Base
(MIB) includes several configuration parameters that correspond to
features available at the control panel of the modem.
The specific items that may be configured via the front panel, and thus via the agent are:
•
Line Encoding
: The
ioLink 4
modem may be configured as either T1 or E1. For modems
configured as T1, the user may choose between Alternate Mark Inversion (AMI) and the default B8ZS.
For modems configured as E1, the user may choose between AMI and the default HDB3. (B8ZS and
HDB3 are zero-suppression encoding algorithms)
.
•
Cable Length:
This is the maximum length of cable from the modem unit to the user’s data source.
Changing this parameter will change the pulse shape of the DSX-1 signal transmitted from the DSX
port to the user’s device. The cable lengths correspond to the standard Line Build Out (LBO) settings
from +0.6 dB to +3.0 dB.
•
Jitter Attenuation:
For input devices with a significant amount of noise, the line interface unit may
provide jitter attenuation. Jitter attenuation is provided by an elastic store (ES) which clocks in the
received bits and then clocks them out of the ES using the clock from the internal jitter attenuation
loop. Inclusion of jitter attenuation produces a delay of 16 bits. The options are to attenuate in the
receive path (default), the transmit path or not at all.
•
Symbol Threshold:
This is a threshold parameter that affects the initial synchronization process of
the link. If the link is performing poorly, especially if it exhibits difficulty establishing synchronization,
lowering this threshold may improve performance. However, too low a value might cause one end of
the link to achieve synchronization to a noise signal. The default value is 50
H
; values less than 28
H
are not recommended.
•
Tracking Threshold:
This is a threshold parameter that affects the continuing synchronization
process of the link. If the link is performing poorly, especially if it loses synchronization, lowering this
threshold may improve performance; however, too low a value might cause one end of the link to
achieve synchronization to a noise signal. The default value is 10
H
; values less than 0A
H
are not
recommended.
4.3 Test Modes
