User's Manual

4.5.3 DX Downstream Cable Channel
The Downstream Cable EIA (DCE) Channel is the channel on which the DOCSIS
cable modem downstream signal is being sent from the CMTS at the head end. It is
set in the ARCXtend Access Point with the standard EIA channel numbers.
*DCE<nnn>, where nnn is an EIA channel number from 23 to 94 and 100 to 138.
Note: In the EIA standard, channels 94 and 100 are adjacent, so there is no gap in
frequency.
The system response to the command is the word “initializing” followed by a series
of internal registers that the CPU is writing to.
Successful completion is noted by displaying the result achieved, plus the actual
ARCXtend center frequency for that channel.
The corresponding 6 MHz channel center frequency from the cable-to-AX1255 and
from AX3155-to-modem is given in the Table below.
Example, to set the Downstream Cable EIA Channel to channel 23:
*log0101 [this typing is not echoed, not shown on the PC screen, the active module,
seeing the login, will logout]
AR250DX[01]>dce23
Initializing...
MT2050 Write Reg 0x01 Data 0xAD
MT2050 Write Reg 0x02 Data 0x1C
MT2050 Write Reg 0x03 Data 0xA8
MT2050 Write Reg 0x04 Data 0x00
MT2050 Write Reg 0x05 Data 0x63
MT2050 Write Reg 0x06 Data 0x10
MT2050 Write Reg 0x08 Data 0x29
MT2050 Write Reg 0x0A Data 0x05
MT2050 Write Reg 0x0F Data 0x0F
MT2050 Write Reg 0x10 Data 0x24
DCE CATV Input US Channel 23 (219 MHz)
4.5.4 DX Downstream Air Frequency
Both the TX and DX module must also be programmed with the DA command and
the same frequency.
The command context is the same as for the TX module, but logging into the DX
Module.
ARCXtend manual, August 2003 4-15