If you too are desperate to hear the screech of a dial up modem (and the drone of a Cisco router) you can build a setup for around £100
- Cisco 3825 ~£20
- Cisco VIC3-4FXS/DID ~£20
- Cisco VWIC2-1MFT-T1/E1 ~£5
- Cisco Digital Modem Module + MICA-6MOD modules ~£25 *
- Cisco PVDM2 Module ~$5 **
- Cisco NM-1CE1T1-PRI ~£10 ***
- E1 Cross Over Cable ~£5 (Look like an Ethernet cable, but isnt)
- 56K Modem ~£10
- RJ11 to BT Adapter with ring capacitor (1-4 depending on how many divices you want to use)
- RAM / CF Card - You at least need 512MB of RAM and 128MB of Flash
* Each MICA-6MOD will handle 6 modem calls, so for a basic system with 4x FXS ports you just need a single module.
** See section on PVDMs
** See section on E1/T1 Cards
A call coming in over the E1 to the modems doesn't require any DSP resources as it's handled by the modem modules, so if you don't have any FXS cards in the router and calls are being routed from somewhere else via the NM-1CE1T1-PR you can get away without any PVDMs.
|Call Flow (Click to expand)|
For my setup with the 3825 I inserted the cards in the following slots:
- NM Slot 1: NM-1CE1T1-PRI
- NM Slot 2: Digital Modem
- HWIC Slot 0: FXS Card
- HWIC Slot 1: VWIC2-1MFT-T1/E1
Remove the blanks and then insert the cards in the slots. Be careful with alignment, it's possible to damage the cards if they're not aligned and forced into the slot. Once inserted, do them up. Finger tight is fine - they really don't need to be tightened with a screw driver.
Once the modules are in their slots you can connect the E1 crossover cable between the PRI and T1/E1 cards. Connect Fa0/0 to your network and power up the router.
I've hosted the configuration on Github Gists so it's hopefully easier to read-
IOS 15.3 for E1 - Europe
IOS 15.3 for T1 - US / JAPAN
- Zefie - Originally posted their setup on Twitter / Youtube
- DrDeke (ShadyTel) - Shared their configuration for a similar setup
- Joe_Z (ShadyTel) - Provided assistance and insight on the setup
- ThoughtPhreaker (ShadyTel) - Helped troubleshoot Dial Up issues