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I need a CSU/DSU to terminate a T1 from our new ISP. It needs to support PPP encapsulation and must have an ethernet output so that we can connect it directly to a switch. What device would you suggest? Thanks!

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Note: Without getting into too much detail, I have to have an external device, not a WIC for our router (we currently have a 2600 series). – Citizen Chin Mar 19 '10 at 18:40
up vote 1 down vote accepted

Adtran is very common, i've used them before. Could you explain what requirements you actually have, that preclude you from using a router with a WIC?

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We have a real Frankenstein setup of a network. We're not in position to tinker with it much now, perhaps down the road. Basically, the simplest thing (simpelst as in working with what we have in terms of time and knowledge) is to get an external CSU/DSU to terminate the T1 and then route it through that to an internet facing switch which then routes to both our VPN and firewall. – Citizen Chin Mar 19 '10 at 19:40
The bottom line is, I need a CSU/DSU for a T1 that supports PPP, and has an ethernet output, not just a serial interface – Citizen Chin Mar 19 '10 at 20:23
OK - then you are asking for a router with an integrated WIC. You say you're asking for a CSU/DSU, which only gives you serial output. If you want that on Ethernet, you're asking for a router. Period. – mfinni Mar 19 '10 at 21:02
AdTran CSU/DSU units are also dirt cheap on eBay if you have a router with a serial interface (like a Cisco 2600 with a Serial WIC). – Chris S Mar 20 '10 at 2:02

You can pickup an old Cisco 1600 or 1700 with a T1 WIC for nothing on eBay.
Just make sure it has the flash card (1600 only) and a power cord.

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Note: Without getting into too much detail, I have to have an external device, not a WIC for our router (we currently have a 2600 series). Sorry, I should have specified th – Citizen Chin Mar 19 '10 at 18:40
@Chin: Yeah, you can but a whole 1600 or 1700 router with the T1 WIC for <$50 (most of the time). Heck, you can get another 2600 with the WIC for <$100. – Chris S Mar 19 '10 at 18:41
And if I wanted to be hard headed and get an external CSU/DSU anyhow, what device would you suggest? :-D – Citizen Chin Mar 19 '10 at 18:50
@Chin, CSU/DSU just switches the line protocol from T1 (aka ISDN-PRI) to Serial. For your setup you want a full router, not just a CSU/DSU. – Chris S Mar 20 '10 at 2:01
nail on the head, sir. – mfinni Mar 20 '10 at 19:41

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