6
October
2004
MIM2-A2-GZ40-00
E1 Parameter Configuration
MIM-2E1 parameters may be configured the web-based Network Management
System (NMS). Configurations for E1 Port 1 apply to E1 Port 2 as well; the two
ports cannot be configured independently. Refer to the NMS User’s Guide
(Document Number NMS-A2-GB20) for more detailed instructions.
Frame Type
Frame type is the E1 data encapsulation method. A frame consists of 248 bits
(8-bit samples of each of the 31 E1 data channels) plus 8 bits of overhead
transmitted at a rate of 8,000 frames per second (1.984 kbps) across the E1 line.
Cyclic Redundancy Check (Default) – Cyclic Redundancy Check (CRC)
scrutinizes data integrity across the E1 line by appending a hexadecimal
checksum to the end of each E1 frame (calculated from the previous E1 frame
contents). The remote modem then makes a similar calculation upon receipt of
each E1 frame and compares it to the checksum of the ensuing E1 frame.
No Cyclic Redundancy Check – NMS offers an option to disable the Cyclic
Redundancy Check function.
Line Code
Line code is the E1 mode of transmission. The two line code options outlined
below both fall within the International Telecommunication Union -
Telecommunication Standardization Sector (ITU-T) G.703 Standards for
Transmission Facilities.
High Density Binary 3 (Default) – High Density Binary 3 (HDB3) is used to
accommodate the minimum ones density requirement in the European public
network. HDB3 line encoding helps prevent loss of synchronization between
the MIM-2E1 and remote E1 equipment by using bipolar violations to
guarantee the presence of pulses in the E1 line.
Alternate Mark Inversion – Alternate Mark Inversion (AMI) simply alternates
positive and negative pulses. Although AMI links typically encounter long
strings of zeros which can potentially cause loss of synchronization between
units, Paradyne products meet the European minimum ones density
requirement internally such that loss of synchronization is prevented between
the MIM-2E1 and remote E1 equipment with AMI just as it is with HDB3.
