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Industrial Telephone Modem

This product is no longer being sold and might not be supported. Product has no replacement part.


✓ Cost effective legacy remote access solution

• Traditional AT command modem
• RS-232 up to 11 bit, 115.2 kbit/s
• V.90, V34, V32bis, V22bis support

✓ Robust industrial solution for long service life in unmanned locations

• Extended temperature –25°C to 70°C (–13°F to 158°F)
• Extensive EMC approvals and tri-galvanic isolated interfaces
• Watchdog and remote configuration

✓ Secure non internet based remote access

• Secure call back function
• Caller ID presentation and answering
• Password protected configuration

✓ Easy to use

• Windows drivers and TD-tool configuration software
• DTR and data dialling
• RS-232, 9-pin D-sub and screw terminals


The TDW-33 is a simple industrial modem designed to allow cost effective and simple remote access to legacy serial industrial equipment. The AT command driven modem is capable of synchronising with a wide range of traditional modem negotiation standards providing data rates up to 56.7 kbit/s.

Designed with remote unmanned industrial locations in mind the modem can operate in extremes of temperature and electromagnetic fields. The complete galvanic separation of all interfaces ensures that earth loops and transients do not interfere with communication.

To keep visits to the site to a minimum a watchdog monitors the modem ensuring constant readiness, and remote re-configuration means that changes to settings can be handled without a site visit.

Firewalls are not an issue as data does not use the internet and with call back security it is impossible for either accidental or deliberate access to any equipment attached to the modem.

The modem is simple to configure using the Westermo TD-tool software; standard commands can easily be entered, and saved configurations downloaded. RS-232 connections can be made using screw connections as well as the standard D-sub.

The modem is designed to be connected to devices with no ability to control dialling so special functions like data dialling and DTR dialling are provided to enable these devices to automatically establish connections.

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Technical Specifications

Industrial Telephone Modem
1 x PSTN 300 bit/s – 56.7 kbit/s
1 x RS-232 300 bit/s – 115.2 kbit/s

Jennifer Mooney-Perrotta

Customer service, Westermo North America

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