Specifications

Alto 818 Installation and Operation
2-30 P/N 66109074001 Rev. D
2.10 MODEMS
Security of an Alto 818 communicating over a modem can be maintained by two methods:
Building ID messages defined with the MODEM command used for identification at the remote
site and requiring the remote site to call back before information is transmitted.
The Alto 818 can accommodate the following asynchronous modem types:
 Dial-up300 - 9600 baud
 Short haul modem (line driver)
 Long haul modem
The SE 5200 smart modem is recommended for use with the Alto 818. This modem is designated
as the SE 5200-L when configured as a local modem or SE 5200-R when configured as a remote
modem. The SE 5200 modem runs at 9600 baud and operates on 115 VAC.
Other modems using the Hayes protocol are compatible with the Alto 818. Non-dial-up modems
can be used with a leased telephone line or a direct cable between the Alto 818 and the host. The
automatic dial-up function of the Alto 818 must be disabled if non-dial-up modems are used. A
summarization of the similarities and differences between short- and long-haul modems is
provided in Table 2-10.
Table 2-9: Short-Haul Modem versus Long-Haul Modem
Feature Short-Haul Modem Long-Haul Modem
Maximum distance from ACU 5 miles
(
8 km
)
50 miles
(
80 km
)
Uses tele
p
hone network? No Yes - leased line
Baud rate U
p
to 9600 U
p
to 9600
Line conditionin
g
re
q
uired No No
S
y
nchronization t
yp
eAs
y
nchronous As
y
nchronous
Transmission mode Full du
p
lex Full du
p
lex
Terminal interface RS-232 RS-232
Line interface 5-wire 5-wire
Manual/automatic e
q
ualization Both Both
Desired dia
g
nostic facilities Remote and local loo
p
back Remote and local loo
p
back
Refer to the modem manufacturer's specifications for additional requirements. Connections to
public telephone line may require notification of the local telephone company.