Comtech EF Data DMD-2050E - Manual (Page 248)

DMD2050E Universal Satellite Modem Efficient Drop and Insert
MN-DMD2050E Revision 2 E–6
E.4.3 Data Formats
The terrestrial data formats compatible with D&I include:
E1 Data T1 Data
PCM-30
PCM-30C
PCM-31
PCM-31C T1-D4
T1-ESF
SLC-96
E.4.3.1 PCM-30
The PCM-30 Mode of Operation supports an E1 Interface with Multiframe Alignment (MFAS) and
Channel Associated Signaling (CAS). The user may independently program n timeslots to drop
and n timeslots to insert where n = 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, or 30. In addition to
the selected drop timeslots, the Transmit Function also extracts the appropriate ABCD signaling
bits from terrestrial timeslot 16 for transmission in IBS Frame as required. Conversely, the
Receive Function extracts received ABCD signaling bits from the IBS Frame and inserts them in
timeslot 16 of the appropriate terrestrial frame. This transmission and reception of ABCD
signaling based upon the drop and insert timeslots is performed automatically and is transparent
to the user. In PCM-30 mode, the user may
not select timeslot 16 as a Drop or Insert Timeslot.
E.4.3.2 PCM-30C
The PCM-30C Mode of Operation supports an E1 Interface with Multiframe Alignment (MFAS)
and Channel Associated Signaling (CAS). In addition, the Drop function verifies the received
terrestrial CRC checksum and the Insert function calculates the required CRC checksum. The
user may independently program n timeslots to drop and n timeslots to insert where n = 1, 2, 3, 4,
5, 6, 8, 10, 12, 15, 16, 20, 24, or 30. In addition to the selected Drop timeslots, the Transmit
Function also extracts the appropriate ABCD signaling bits from terrestrial timeslot 16 for
transmission in IBS Frame as required. Conversely, the Receive Function extracts received
ABCD signaling bits from the IBS frame and inserts them in timeslot 16 of the appropriate
terrestrial frame. This transmission and reception of ABCD signaling based upon the Drop and
Insert timeslots is performed automatically and is transparent to the user.
In PCM-30C Mode , the
user may not select timeslot 16 as a Drop or Insert Timeslot .
E.4.3.3 PCM-31
The PCM-31 Mode of Operation supports an E1 Interface with no Multiframe Alignment (MFAS)
or Channel Associated Signaling (CAS). The user may independently program n timeslots to