15 t1 programmable in-band loop code generator, T1 programmable in-band loop code generator – Rainbow Electronics DS26519 User Manual
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DS26519 16-Port T1/E1/J1 Transceiver
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9.9.15 T1 Programmable In-Band Loop Code Generator
The DS26519 can generate and detect a repeating bit pattern from one to eight bits or 16 bits in length. This
function is available only in T1 mode.
Table 9-33. Registers Related to T1 In-Band Loop Code Generator
REGISTER
FRAMER 1
ADDRESSES
FUNCTION
Transmit Code Definition Register 1
(
)
1ACh
Pattern to be sent for loop code.
Transmit Code Definition Register 2
(
)
1ADh
Length of the pattern to be sent.
Transmit Control Register 3 (
)
183h
TLOOP bit for control of number of patterns being
sent.
Transmit Control Register 4 (
)
186h
Length of the code being sent.
Note: The addresses shown above are for Framer 1.
To transmit a pattern, the user will load the pattern to be sent into the Transmit Code Definition Registers (
and
) and select the proper length of the pattern by setting the TC0 and TC1 bits in Transmit Control
Register 4 (
). When generating a 1-, 2-, 4-, 8-, or 16-bit pattern both
must be filled with
the proper code. Generation of a 3-, 5-, 6-, and 7-bit pattern only requires
accomplished, the pattern will be transmitted as long as the TLOOP control bit (
.0) is enabled. Normally
(unless the transmit formatter is programmed to not insert the F-bit position) the framer will overwrite the repeating
pattern once every 193 bits to allow the F-bit position to be sent.
As an example, to transmit the standard “loop-up” code for Channel Service Units (CSUs), which is a repeating
pattern of ...10000100001..., set TCD1 = 80h, TC0 = 0, TC1 = 0, and
.0 = 1.