
DS26401 Octal T1/E1/J1 Framer
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11.11 E1 Transmit Signaling Operation
There are two methods to provide transmit signaling data—processor-based (i.e., software-based) or hardware-
based. Processor-based refers to access through the transmit signaling registers, TS1-TS16, while hardware-based
refers to using the TSIG pins. Both methods can be used simultaneously.
11.11.1 Processor-Based Mode
In processor-based mode, signaling data is loaded into the Transmit Signaling registers (TS1–TS16) via the host
interface. On multiframe boundaries, the contents of these registers are loaded into a shift register for placement in
the appropriate bit position in the outgoing data stream. The user can utilize the Transmit Multiframe Interrupt in
Latched Status Register 1 (TLS1.2) to know when to update the signaling bits. The user need not update any
transmit signaling register for which there is no change of state for that register.
Each Transmit Signaling Register contains the TS16 CAS signaling (E1) for one time slot that will be inserted into
the outgoing stream if enabled to do so via TCR1.6. Signaling data can be sourced from the TS registers on a per-
channel basis by utilizing the Software Signaling Insertion Enable registers, SSIE1 through SSIE4.
In E1 mode, TS16 carries the signaling information. This information can be in either CCS (Common Channel
Signaling) or CAS (Channel Associated Signaling) format. The 32 time slots are referenced by two different channel
number schemes in E1. In “Channel” numbering, TS0 through TS31 are labeled channels 1 through 32. In “Phone
Channel” numbering TS1 through TS15 are labeled channel 1 through channel 15 and TS17 through TS31 are
labeled channel 15 through channel 30.
Time Slot Numbering Schemes
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
TS
Channel
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
Phone
Channel
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
11.11.2 Hardware-Based Mode
In Hardware-Based mode, signaling data is input via the TSIG pin. This signaling PCM stream is buffered and
inserted to the data stream being input at the TSER pin.
Signaling data may be input via the Transmit Hardware Signaling Channel Select (THSCS) function, the framer can
be set up to take the signaling data presented at the TSIG pin and insert the signaling data into the PCM data
stream that is being input at the TSER pin. The user has the ability to control which channels are to have signaling
data from the TSIG pin inserted into them on a per-channel basis. The signaling insertion capabilities of the framer
are available whether the transmit side elastic store is enabled or disabled. If the elastic store is enabled, the
backplane clock (TSYSCLK) can be 2.048MHz. If IBO mode is enabled then TSYSCLK may also be 4.096MHz,
8.192MHz, or 16.384MHz.