DS21458LDK Maxim Integrated, DS21458LDK Datasheet - Page 58

• Manufacturer Part Number: DS21458LDK
• Description: Network Controller & Processor ICs
• Manufacturer: Maxim Integrated

DS21455/DS21458 Quad T1/E1/J1 Transceivers
10.2 T1 Transmit Transparency
The software-signaling insertion-enable registers, SSIE1–SSIE4, can be used to select signaling insertion
from the transmit-signaling registers, TS1–TS12, on a per-channel basis. Setting a bit in the SSIEx
register allows signaling data to be sourced from the signaling registers for that channel.
In transparent mode, bit 7 stuffing and/or robbed-bit signaling is prevented from overwriting the data in
the channels. If a DS0 is programmed to be clear, no robbed-bit signaling will be inserted nor will the
channel have bit 7 stuffing performed. However, in the D4 framing mode, bit 2 will be overwritten by a
zero when a yellow alarm is transmitted. Also, the user has the option to globally override the SSIEx
registers from determining which channels are to have bit 7 stuffing performed. If the T1TCR1.3 and
T1TCR2.0 bits are set to one, then all 24 T1 channels will have bit 7 stuffing performed on them,
regardless of how the SSIEx registers are programmed. In this manner, the SSIEx registers are only
affecting channels that are to have robbed-bit signaling inserted into them.
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