PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 121

• Manufacturer Part Number: PEF2091
• Description: ICs for Communications(ISDN Echocancellation Circuit)
• Manufacturer: Siemens Semiconductor Group

The last setting for the M4 bits complies with ANSI T1.601 without need for further
software efforts. Note that this is the default setting for the M4 bits in all non repeater
modes (see Table 26). Note also that this filtering method setting can be combined with
the CRC filtering method.
In addition, the verification of the M4 bits is completely independent of the verification of
bits M51, M52 and M61. This allows using the M4 bits in compliance with ANSI T1.601
(Triple Last Look), and still retain the freedom to use bits M51, M52 an M61 for other
purposes (i.e. control functions, or even very low rate data transmission).
Control of the Single Bits is mode independent. This allows more flexibility, e.g. in
repeater applications.
Selection of the filtering method is controlled via MON-8 messages. It is therefore
available in stand-alone mode as well as in µP mode.
Definitions
As selection of the verification method for Single Bits is done via MON-8 messages, it is
convenient to recall the format of MON-8 messages, which is given in Table 25 below.
For more details on MON-8 messages, see "MON-8 Codes", page 228.
Table 25
r:
D0…7 Local command – 00 … FF
The MON-8 commands used to control the verification method are all local functions.
The Register bit "r" should therefore be always set to "0".
For definition of the Single Bits, see "Single Bits Channel", page 69. In what follows we
will refer to Bits M41 to M48 as "M4 Bits". Bits M51, M52 and M61 will be referred to as
"Additional Overhead Bits".
Semiconductor Group
MON-8
1 0 0 0
Register address – 0 = local function register
Format of MON-8-Messages
1. Byte
Register | Addr.
– 1 = internal register
– 00 … FF
r | 0 0 0
H
H
= local function code
= internal register address
121
Local Command (Message/Data)
D7 D6 D5 D4 D3 D2 D1 D0
Operational Description
2. Byte
Data Sheet 01.99
PEB 2091
PEF 2091