Nortel BayStack Instant Internet 100-S Using Manual page 253

4
Configure any of the following:
• Starting Channel – An E1 line has 32 channels (1 to 32). When you
order a fractional E1 service, only part of the channels are available for
data transmission. In some cases the Instant Internet unit may need to
send data on a block of channels that do not start on Channel 1, so you
must change the starting channel.
• Channels are – Depending on what your E1 service provider assigns you,
you will select Consecutive (every one) or Alternating (every other one).
In some rare cases, you may have a block of channels available but may
be able to send data only on every other channel. In this case, select
alternating.
• Line style – The E1 bandwidth is used to carry E1 performance data and
commands, such as loopback. This data may follow one of two standards:
ANSI T1.403 or AT&T 54016. This value should be supplied by your E1
service provider. If this value is set incorrectly, the performance data may
not be available and a loopback request may not be recognized.
• Clock – If the network provides the clock for the E1 line, select External.
If the Instant Internet unit provides the clock, select Internal. In almost all
cases, the network provides the clock.
• Auto loopback – Auto loopback is used for diagnostics and allows the
network to force the Instant Internet unit into loopback. Leave this check
box selected unless directed otherwise by a technical support
representative.
• CRC4 checksum – CRC4 checksum allows you to enable or disable the
CRC4 checksum bits.
• NFAS – Select NFAS to require both NFAS and FAS word for frame
sync. If NFAS is not selected, only FAS word is needed for frame sync.
• Backup interface – A ISDN connection is available for use as a backup
connection to the Internet should your E1 connection become
unavailable.
Using the BayStack Instant Internet Management Software Version 7.11
Chapter 8 Advanced communications configuration 253