Dolby Laboratories DP503 - Manual (Page 87)

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BONDING-1 56
This version of inverse multiplexing is identical to BONDING-1 64
but is used when connecting to either 56 kbps ISDN or Switched 56
lines.
AIM DELTA 56
AIM Delta is a version of inverse multiplexing which provides
compatibility between 56 kbps and 64 kbps ISDN or Switched 56
lines. In a situation where a 64 kbps site calls a 56 kbps site, 3 ISDN
BRI lines are required. In the default Dolby Fax format, instead of
making four calls, a Delta call places five calls for a total of 280 kbps.
The Ascend ISDN unit converts the 280 kbps to 256 kbps and “bit
stuffs” the leftover bandwidth. As ISDN service proliferates
throughout North America, there are fewer and fewer 56 kbps ISDN
installations. International ISDN is always 64 kbps.
1 CHNL 56/1 CHNL 64
This type of call does not utilize inverse multiplexing since only one
call is placed.
LEC
Local Exchange Carrier is another term for RBOC. Besides the seven
RBOCs, other "specialty" local carriers that compete for local business
service.
NT-1
An isolation device, analogous to a transformer, which isolates the CPE
(Customer Premises Equipment) such as the terminal adapter or audio
codec, from the network and vice versa. The NT-1 is typically located with
the terminal adapter and also converts the 2 wire circuit from the phone
company into a 4 wire circuit. The Ascend Multiband VSX ISDN unit
supplied with Dolby Fax has the NT-1 built-in.
PRI (Primary Rate ISDN)
An ISDN interface that provides 23 64 kbps digital "B" (Bearer) channels
of voice or data and one 64 kbps digital "D" (Delta) channel for signaling.
ISDN PRI is sometimes referred to as 23B+D.
Basic Rate Interface (BRI)
An ISDN interface that provides two 64 kbps digital B (Bearer) channels
for voice or data and one 16 kbps signaling D (Delta) channel.
RBOC
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