Black Box MWU2000-X21, MWU2000-G703, MWU2000-V35 manual Superframe Method, D4 Yellow Alarm Method

2.048Mbps Wireless Modem

Superframe Method

Each frame transmitted to (or received from) the end equipment is comprised of 193 bits, numbered 1 to 193. Bit numbers 2 to 193 are used for data. The first bit of each frame is designated an F-bit, and is used for purposes such as frame alignment, performance monitoring (CRC check) and providing a data link. There are two alternative methods for allocation of F-bits:

•ESF: A 24-frame multiframe. F-bits provide frame alignment signal (FAS), a 4Kbps data link with the connected equipment (DL), and CRC-6 block check field.

•D4: A 12-frame multiframe. F-bits provide frame and multiframe alignment signal (No CRC or data link). Set this parameter to 0 (D4) or 1 (ESF) in accordance with the connected end equipment.

D4 Yellow Alarm Method

Yellow alarm is an indication, using the D4 multiframe method, that the sending equipment is unsuccessful in synchronizing with the receiving equipment. There are two methods of transmitting the yellow alarm message:

•D4 bit 2 mode: Setting bit number 2 of all channels to 1

•D4 F-bit mode: Setting a specific F-bit to 1

Set the D4 yellow alarm method to 0 (bit 2 mode) or 1 (F-bit mode) in accordance with the configuration of the connected end equipment.

Pulse Shape

The current selection is displayed (the NOT DEFINED message is displayed if LIU used is not T1). The selection should be made according to the length of the line connecting the terminal equipment to the 2.048Mbps Wireless Modem, and according to the type of application (CSU or DSU network interface). The selection affects the pulse mask used in the

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