The
ASM-40 operates full or half duplex over
unconditioned telephone lines or coaxial
cable and can also be used as a rate and
interface converter. The ASM-40 operates
at eight selectable data rates, with a range
of up to 1.75Km. The data rates of 64, 256,
512, 1024 and 2048 are transmitted at line
speeds of 2.048Mbps; the data rate of 1544
at 1544Kbps; and data rates of 384, 768
and 1536 are transmitted at 1536Kbps. The
independent selection of line and DTE data
rates enables the ASM-40 to be used also
as a rate converter. An optional data rate
of 1920Kbps is also available. The modem’s
analog interface is in compliance with CCITT
G.703. On the digital side, a choice of
V.35, RS-422/V.36, X.21 or G.703/HDB3 interfaces
is available. This enables the ASM-40 to
also perform as an interface converter,
a rate converter or a repeater for G.703.
Transmit timing is provided internally,
or derived externally from the data terminal
or from the receive signal. The ASM-40 features
V.54 diagnostic capabilities to perform
local analog loopback and local and remote
digital loopback. An internal test pattern
can be generated to provide end-to-end integrity
testing. The ASM-40 is available as a desk-top
unit or as a rackmount card for 19"
rack holding up to 14 cards.
