Editing Atari 830

{{Infobox computer peripheral
| name         = Atari 830 Acoustic Modem
| image        = [[File:Atari 830 Acoustic Modem (operator's manual figure 4).png|260px|frameless]]
| caption      = The 830 with a handset over its cups, from Atari's operator's manual
| manufacturer = Novation, for Atari, Inc.
| type         = Acoustic coupler modem
| release_date = Introduced January 1980; shipping from about autumn 1980<ref name="faq" />
| price        = US$199.95 (announced 1980)<ref name="faq" />
| interface    = RS-232, 25-pin socket, through the [[Atari 850]] Interface Module<ref name="faq" />
| compatible   = [[Atari 400]] and [[Atari 800]] with an Atari 850<ref name="om" />
| power        = Novation 901017 adaptor (Atari CA016751), 20 V AC; 7 W<ref name="faq" />
}}

The '''Atari 830 Acoustic Modem''' is a 300 bit/s Bell 103 modem for the Atari 8-bit computers. The user dials the call on an ordinary telephone and then sets the handset in the modem's two rubber cups, which carry the tones to and from the line. Novation made it for Atari, based on its CAT modem.<ref name="faq">Michael D. Current (ed.), ''Atari 8-Bit Computers: Frequently Asked Questions'', comp.sys.atari.8bit FAQ, last modified 2 August 2026: section 5.1.1 (the Atari 830 modem), section 6.2 (power requirements), section 6.4 (the Communicator kit CX484) and section 11.1 (history, 1980). [https://mcurrent.name/atari-8-bit/faq.txt mcurrent.name]. Community reference.</ref> It has no SIO connection of its own and connects to the computer through serial port 1 of the [[Atari 850]] Interface Module.<ref name="om">Atari, Inc., ''Atari 850 Interface Module Operator's Manual'' (C017651, 1982): installation, use of the 830, troubleshooting and the 830 test mode. Hosted here as [[:File:Atari 850 Interface Module Operator's Manual C017651.pdf]].</ref>

Atari introduced the 830 with the 850 and the [[Atari 825]] printer at the Winter Consumer Electronics Show in January 1980, and shipped them in about the autumn of that year.<ref name="faq" /> It was also sold in The Communicator kit (CX484), which held an 850 with its adaptor, the 830, the TeleLink I cartridge and an hour of free time on each of Dow Jones, The Source and CompuServe.<ref name="faq" /> The Communicator II kit (CX488), announced in June 1982, paired the direct-connect [[Atari 835]] with the TeleLink II cartridge.<ref name="faq" />

== Specifications ==

{| class="wikitable styled-table" style="width:70%; text-align:center;"
|+'''Atari 830 specifications (FAQ section 5.1.1)'''
! Item !! Value
|-
| Type || Acoustic coupler, frequency shift keying
|-
| Speed || Up to 300 bit/s
|-
| Standard || Bell 103
|-
| Originate mode || Sends 1,270 Hz mark, 1,070 Hz space; receives 2,225 Hz mark, 2,025 Hz space
|-
| Answer mode || Sends 2,225 Hz mark, 2,025 Hz space; receives 1,270 Hz mark, 1,070 Hz space
|-
| Receive sensitivity || -45 dBm
|-
| Indicators || Ready and Power lights on top
|}

The connector is a 25-pin RS-232 socket wired as a modem (DCE): transmit data on pin 2, receive data on pin 3, clear to send on pin 5, data set ready on pin 6, signal ground on pin 7 and carrier detect on pin 8. Atari's CX87 modem cable, supplied with the 830, joins it to the 850's 9-pin port.<ref name="faq" />

== Controls ==

[[File:Atari 830 Acoustic Modem controls (operator's manual figure 3).png|thumb|right|300px|End panel controls, from figure 3 of the operator's manual]]
The end panel has two slide switches, the power jack and the I/O connector. The O/OFF/A switch turns the modem off in the centre position and on in originate (O) or answer (A) mode; the F/TST/H switch selects full duplex, the self-test, or half duplex.<ref name="om" /><ref name="faq" />

To call another computer, Atari's procedure is to set O/A to O and F/H to suit the other system, dial the number, and when the answering tone is heard put the handset into the cups with its cord towards the connector. The red READY light comes on when the modem is ready. To answer a call, set O/A to A, pick up the telephone and put the handset in the cups. For two Atari users, one modem must be in originate and the other in answer.<ref name="om" /> The computer needs the Atari BASIC, Assembler Editor or TeleLink I cartridge to use the modem, and the 850 and the modem must be switched on before the computer.<ref name="om" />

== Power ==

The modem has its own adaptor. The unit shipped with the 830 is a Novation 901017 (Atari CA016751) marked "Use with 830 Modem Only", rated 20 V AC 400 mA; the FAQ gives the requirement as 20-24 V AC.<ref name="faq" /> Atari warns that using the modem adaptor on any other Atari unit may seriously damage it.<ref name="om" />

== Self-test ==

The operator's manual gives a loop test using the TeleLink I cartridge. Set O/A to originate and F/H to TEST; if there is no tone, the modem is faulty. Dial a single digit on the telephone to get a quiet line, put the handset in the cups at once, wait for READY and type a message: the modem sends it back through the 850 to the screen, where it can be checked for errors. Then move O/A to A with the handset still in place, wait for READY and repeat. Dialling one digit gives about 30 seconds of quiet line; calling a friend whose mouthpiece is covered gives longer.<ref name="om" />

== Troubleshooting ==

Atari's manual says noise or a weak signal on the telephone line is the most likely cause of problems, and that redialling usually clears it.<ref name="om" />

{| class="wikitable styled-table" style="width:100%;"
|+'''Atari 830 troubleshooting (operator's manual C017651)'''
! Symptom !! Check
|-
| READY light off || Modem power on; handset seated with its cord towards the connector; O/A set to originate for a time-share service (one modem in each mode between two users); F/H at FULL or HALF, not TEST; the far modem Bell 103 compatible, not Bell 202
|-
| Every character shown twice || Set full duplex if the remote computer echoes characters, half duplex if it does not
|-
| Garbled display || Handset fully seated in the cups; both ends at the same speed (300 bit/s or less); a clean tone on the line, without other tones, clicks or voices; redial
|-
| Nothing sent or received || O/A switch setting; 830 and 850 switched on; loose cables
|}

The FAQ lists the two 850 operator's manuals, C015953 (1980) and C017651 (1982), as the 830's documentation.<ref name="faq" />

== Related pages ==

* [[Atari 850]]
* [[Atari 835]]
* [[Atari 850 Documentation]]

== References ==

<references />

{{Navbox-AtariPeripherals|state=collapsed}}

[[Category:Atari Systems]]