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System Overview
2-13
CADM
CADM is a digital voice channel used for foreign applications only. This circuit type should nev-
er be selected for domestic applications.
PCM-T (Pulse-Coded Modulation)
PCM-T is selected when the Voice II/ASP Channel module is used but a higher fixed data rate of
64 kbps is desired. PCM-T bypasses the ASP circuit so that the 64 kbps input remains 64 kbps at
the output. 64.8 kHz of aggregate bandwidth are consumed by a PCM-T voice channel. The extra
800 Hz of bandwidth are used for overhead and synchronization bits; when an ASP channel is
configured, the REMAINING BANDWIDTH figure is reduced by 64.8 kHz. The output level of
an ASP channel may be set as a channel parameter. ASP AUTO FRAME Plus firmware is re-
quired for support of PCM-T voice circuits.
TOR
TOR is a digital voice channel used for foreign applications only. This circuit type should never
be selected for domestic applications.
U-ADPCM
U-ADPCM is selected when the Universal Voice Card/ADPCM (UVC/ADPCM) is installed in
the slot associated with the channel number. The UVC/ADPCM allows selection of variable AD-
PCM rates, as well as the voice encoding scheme. The output level of a UVC/ADPCM channel
may be set as a channel parameter. The Universal AUTO FRAME Module (036P248-026) is re-
quired for support of UVC/ ADPCM.
TID-III
The TID-III (Time Independent Data) Channel Module allows true isochronous/pleischronous
data communication in a MEGAMUX PLUS TDM.
The TID-III Data Channel Module accepts RS-422 data and clock inputs at any one of 18 standard
rates from 1.0 Kbps to 1.024 Mbps. The TID-III can be programmed to accommodate special
rates or to automatically track variable rate input clocks up to a specified maximum. The TID-III
Data Channel Module utilizes both RS-422 clock and data inputs. These inputs are time indepen-
dent from the multiplexes timing. The isochronous/pleischronous data is converted to the next
higher TDM synchronous data rate. Time independent data is then recovered at the remote end
of the link and the appropriate clock is generated by a Numerically Controlled Oscillator (NCO)
board for output of data.
The TID-III Data Channel Module consists of three pc boards, the transmitter board consists of
logic interface circuits, control/status circuits, buffers, and front panel switches and status indica-
tors. The receiver board contains a data correlator, FIFO buffers and data accumulator circuits.
The numerically controlled oscillator (NCO board) is located on the receiver board. The NCOs
function is to generate the appropriate clock for data output. An RS-422 interface piggyback
board mounts to the receiver card. The TID-III Data Channel Module assembly mounts into the
main shelf.
When installed in two MEGAMUX PLUS TDMs, the TID-III Data Channel Module pair estab-
lishes a full duplex data link between corresponding TDM sites.
TID-III Data Channel Modules may be installed at both ends of the link, or correspondingly, a
TID-III Data Channel Module may be on one end of a link with either a TID I or TID-II (ECH-
12) Data Channel Module installed on the remote end.
036R660-000, Issue 10
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